Baby breathing difficulties
Apnoea attack, or near cot death, occurs when a baby stops breathing for a few seconds. It affects around 500 babies a year.

Back pain

Bird flu
The BBC News website looks at bird flu - and the fears it could spread between humans.

Biliary Atresia
Around 50 children are born with biliary atresia every year in England and Wales. The condition affects the liver and is potentially fatal if not operated on early.

Binswanger's disease
Lawyers acting for Edgar Pearce - the Mardi Gra bomber - have claimed he suffers from Binswanger's disease, a rare form of dementia that can change the way people think.

Body Dysmorphic Disorder
A Scottish hospital has launched an inquiry after a surgeon agreed to remove healthy limbs from patients suffering from a psychological disorder. BBC News Online looks at the condition.

Boxing
Many doctors see boxing as an unacceptably dangerous sport - the BMA would like to see it banned.

Brain haemorrhage in pre-term babies
One of the risks to babies born prematurely is that their undeveloped blood vessels will bleed into the brain.

Brain tumours
Brain tumours information

Burns and scalds
How to avoid and treat burns and scalds.

Cannabis
Opinion is sharply divided over whether cannabis should be legalised for medicinal use.

Cataracts
One in three people over the age of 65 has a cataract. Left untreated cataracts can significantly impair vision.

Cerebral aneurism
An aneurism is a dilation, or swelling, of a blood vessel (where part of the vein or artery inflates like a balloon).

Cholera
Cholera is an intestinal infection caused by a bacteria - and is often linked to contaminated supplies of drinking water.

Cleft lip and palate
A baby which was abandoned by its parents in Portugal was identified partly through a distinctive cleft upper lip. BBC News Online looks at the condition.

Clinical trials

Coeliac disease
Coeliac disease is a gut disorder which can strike at any age.

Collapsed lung
A collapsed lung prevents the sufferer from absorbing life-giving oxygen into the blood stream in the normal way.

Complementary medicines: A guide
From acupuncture to yoga, all you need to know about the most commonly used therapies.

Conjoined twins
Conjoined twins are a rare phenomenon.

COPD (respiratory disease)
Scientists are developing a treatment for a form of lung disease which is one of the UK's biggest killers.

Crohn's disease
Information on the inflammatory gut disorder Crohn's disease.

Cystic fibrosis
Cystic fibrosis is an life-threatening inherited genetic disease.

Deep vein thrombosis
Deep vein thrombosis is the formation of a blood clot in one of the deep veins of the body, usually in the leg.

Depression
Depression is a common mental illness which is estimated to affect up to one in five Britons at some point in their lifetime. Famous sufferers include Sir Winston Churchill.

Diabetes
The hormonal condition diabetes is on the increaseas people lead increasingly unhealthy lifestyles. If untreated it can cause very serious health problems.

Dioxins
Dioxins are present everywhere and are known to be a serious heath threat - BBC News Online looks at the facts.

Diverticular disease
Diverticular disease is a condition which occurs when pouches of tissue, commonly known as diverticula, pass through the muscular layer of the bowel.

Down's syndrome
Down's syndrome is a genetic condition which affects about one in every 1,000 babies born in the UK.

Drugs
The arrival of recreational drugs has created an explosion in use. BBC News Online looks at the major illegal drugs.

Dysentery
Dysentery, an infection of the digestive system, can kill if not treated.

Dystonia
Dystonia is an incurable neurological movement disorder thought to affect at least 40,000 in the UK alone.

E. coli infection
E. coli is a common bug which is present everywhere in the environment. Mostly it helps people to stay healthy, providing the body with many vitamins, such as vitamin K. But some strains - such as the 0157 strain - are potentially fatal.

Eating disorders
Eating disorders are responsible for the highest number of deaths from psychiatric illness.

Ebola and other tropical viruses
BBC News Online examines the facts behind terrifying outbreaks of haemorrhagic fevers in Africa and beyond.

Ecstasy
The dangers of the recreational drug Ecstasy are still not fully understood - and, as some tragic cases have proved, it can damage health.

Ectopic pregnancy
One of the most devastating complications of pregnancy is if the embryo starts to grow outside the womb - an ectopic pregnancy.

Eczema
US authorities have ruled two eczema creams should carry warnings that they may increase the risk of cancer.

Electro-convulsive Therapy
Once a commonly used - and controversial - treatment for a variety of mental problems, ECT still bears a stigma despite advances which have made it far safer and more effective.

Emergency contraception
How emergency contraception methods work.

Emphysema
Emphysema is a progressive lung condition which leaves sufferers struggling for breath.

Encephalitis
Insect-borne diseases are spreading around the world - find out about some of the most common infections.

Endometriosis
Endometriosis is a painful, chronic disease that is estimated to affect up to 25% of all women.

Epilepsy
Epilepsy is a common neurological disorder which causes fits. At any one time 300,000 people in the UK have active epilepsy.

Epstein-Barr Virus
Epstein-Barr virus (EBV) occurs world-wide and infects most people at some point in their lives.

Erectile dysfunction
Erectile dysfunction is the repeated inability to get or keep an erection firm enough for sexual intercourse.

Exhaust emissions
Vehicle emissions can have a serious impact on health.

Laser Eye Surgery
An explanation of the surgical procedure intended to reduce a person's dependency on glasses or contact lenses.

Fat
Fat is an essential part of the diet, but lots of people eat more fat than they need or is good for them.

Female genital mutilation
The cultural and religious practice of female circumcision is a health hazard that maims and kills young women across the world.

Female sexual dysfunction
Inadequate sexual function in women is a complex problem that can have many different causes.

Fibromyalgia
Fibromyalgia is a condition which causes widespread pain and severe fatigue.

Flu
Flu and its complications can kill, but most healthy people can shake it off in a few days.

Food additives
The possible health risks of food additives are the subject of fierce controversy among experts.

Gastro oesophageal reflux disease

Glaucoma
BBC News Online examines what causes glaucoma and how it is treated.

Goldenhar Syndrome
The rare Goldenhar Syndrome leaves babies with an underdeveloped face and is thought to affect just 75 children in the UK.

Group B streptococcus infection
Group B streptococcus is the most common cause of life-threatening infections in newborn babies in the UK.

Guillain-Barré Syndrome
Guillain-Barré Syndrome is a frightening and disabling disease which strikes suddenly, sometimes with devastating effect.

Hayfever
How can it be avoided? And what causes it in the first place? BBC News Online investigates.

Hepatitis B
Hepatitis B is the most common serious liver infection in the world. It is thought to be the leading cause of liver cancer.

Hepatitis C
Hepatitis C is a virus which can cause serious liver problems.

Hernia
Prince Charles is far from alone in needing an operation to repair a hernia. It is the commonest male operation performed in the UK, with the NHS performing over 100,000 hernia repairs every year.

Heroin
Heroin use is on the increase. There are about 40,000 registered addicts in the UK, but the real figure could be four times that number. Customs seizures are also at a record high.

HIV
HIV has killed millions of people world-wide since it was first identified as a threat to public health more than 20 years ago.

Human growth hormone
Human growth hormone (HGH) has been helping stunted children in the UK to grow normally since 1959.

Human Papilloma Virus
Human papilloma viruses or HPVs are a group of more than 80 different types of virus, including those that cause genital warts. BBC News Online looks at what they are and what they do.

Hypertension
Hypertension, or high blood pressure, can lead to serious complications, including heart attacks.

Hysterectomy
A hysterectomy is a major surgical procedure, involving removal of the uterus.

Infant fever
Many babies suffer from fever, but only rarely is it something to worry about.

Irritable bowel syndrome
Irritable bowel syndrome is a common and painful disorder about which relatively little is still known.

IVF
Around 6,000 babies a year are born in the UK to otherwise infertile couples as a result of in vitro fertilisation.

Infectious disease
Malaria is a public health problem in some 90 countries, and causes between 1.5 and 2.7 million deaths world-wide each year.

Japanese encephalitis
Japanese encephalitis is a disease caused by a virus transmitted by mosquitoes - in severe cases it leads to a deadly inflammation of the brain.

Kidney failure
Kidney failure is a serious disease which can have a major impact on life, and can ultimately be fatal. However, it can be successfully treated.

Knee cartilage
The Queen is to undergo a minor operation to remove torn cartilage in her knee for the second time in less than a year. BBC News Online examines the problem.

Knee injuries
The knee injury suffered by Ruud van Nistelrooy is typical of those suffered by footballers, as BBC News Online discovers.

Legionnaires' disease
Legionnaires' Disease is a severe form of pneumonia caused by a bacteria that contaminates water supplies. It can be fatal.

Leprosy
Leprosy is a painful condition which, although curable, can leave sufferers deformed and crippled if left untreated.

Lupus
Lupus is a disease that can affect many parts of the body and occurs when the immune system - the body's natural defence against infections - goes wrong.

Lyme disease
A tick-borne disease which can cause severe joint problems is becoming more prevalent in Europe. BBC News Online has the facts about Lyme disease.

Lymphatic filariasis
Lymphatic Filariasis, also known as elephantiasis, is a severely disfiguring disease which affects 120m around the world.

Malaria
Malaria kills over a million people a year and is second only to tuberculosis in its threat to world health.

Marburg virus
The Marburg virus has killed more than 140 people in a major outbreak in Angola

Meningitis and septicaemia
Meningitis is an inflammation of the brain lining and is mostly found in bacteria and viruses - the bacterial form is the more life-threatening.

Menopause
The facts about the menopause and the devastating consequences of premature menopause.

Menstrual problems
Menstrual problems are one of the four most common reasons why women of a reproductive age see their GP.

Methadone
Methadone is used as a way to wean addicts off heroin, but can be addictive itself.

Migraine
Migraine is a debilitating condition characterised by severe headaches and a range of other physical symptoms which affects approximately 10% of the UK population.

Miners' lung disease
A lifetime of breathing in coal dust can put miners at risk of developing respiratory diseases like pneumoconiosis and emphysema.

Minor strokes
Minor strokes can cause temporary weakness or numbness in an arm or leg, or may be warning signs preceding a major stroke.

Motor neurone disease
Motor neurone disease is a progressive fatal condition that causes muscle wastage.

MRSA 'superbugs'
BBC News Online examines what we can do about MRSA, the so-called "superbug" scourge of the wards.

Multiple births and fertility treatment
In the last 30 years, there has been a huge rise in multiple births, due mainly to the increasing use of fertility treatment.

Multiple sclerosis
Multiple sclerosis is an incurable degenerative disease that attacks the central nervous system. Drugs are available to treat the symptoms but they are very expensive, and not universally available on the NHS.

Mumps
Mumps is a viral infection that most make an easy recovery from but can, rarely, lead to severe complications.

Munchausen's Syndrome by Proxy
Munchausen's Syndrome by Proxy is a controversial condition about which little is still known.

Muscular dystrophy
Article about the different types of muscular dystrophy

Myalgic encephalomyelitis
Myalgic encephalomyelitis or chronic fatigue syndrome has only been recognised by doctors in recent years after originally being dismissed as 'yuppie flu'.

Nosebleeds
Nosebleeds are more often annoying than a serious health threat, although they can indicate the presence of other underlying illnesses.

Q&A: Obesity
Obesity is a major issue around the world, and as more and more people put on excess weight it is a problem that is only likely to get worse.

Obsessive-Compulsive Disorder
Obsessive-Compulsive Disorder is an anxiety disorder in which the sufferer is compelled to undertake bizarre and upsetting behaviour in response to irrational thoughts or images.

Osteoporosis
Osteoporosis - a gradual weakening of the bones - affects one in three women and one in 12 men, and is on the increase among the young.

Ovary grafting
BBC News Online examines the possibilities, benefits and potential drawbacks of the world's first 'ovary graft' operation.

Oxygen injury therapy
Rally driver Colin McRae is reputed to have used a pressurised oxygen treatment to speed his recovery from injury.

Pancreatitis
Acute pancreatitis is a sudden inflammatory condition which can cause severe symptoms.

Parkinson's Disease
Parkinson's Disease afflicts the nervous system. It is incurable, but the symptoms can be managed.

Q&A: Passive smoking
BBC News Online examines the evidence on the health risks of breathing in other people's tobacco smoke.

Pasteurellosis
What is rabbit flu and how can it infect humans?

Peptic Ulcer Disease
Peptic ulcer disease is a condition associated with a break in the lining of either the stomach or portion of the small intestine, known as the duodenum.

Personality disorder
To many people, personality disorder conjures up images of violence and fear, but doctors are undecided about who has a disorder, let alone how to treat it.

Pesticides
Pesticides have been associated with everything from cancer and infertility to Gulf War syndrome and eye abnormalities, but solid evidence proving a link has been thin on the ground.

Plague
Plague killed millions of people in Europe in the Middle Ages, when it was also known as the Black Death.

Pneumonia
Pneumonia is a common respiratory disease, and kills around one in 20 people who contract it.

Q&A: Polio

Post-traumatic stress disorder
Those recovering from a traumatic event - such as a school shooting or a major crash - are at risk of severe psychological harm.

Premature babies
BBC News Online examines the risks associated with a premature birth.

Prion diseases
Prion diseases are all fatal and include the new variant of CJD - the brain disorder thought to be caused by eating BSE-infected beef.

Progressive supranuclear palsy
A closer look at this condition, closely related to Parkinson's disease.

Prozac
The anti-depressant drug Prozac has transformed millions of lives since it was launched in the 1980s, but it is not the miracle that some claim.

Pre-Menstrual Syndrome
Pre-Menstrual syndrome is a potentially debilitating cluster of up to 150 symptoms that affects up to a half of all women between the ages of 20 and 50.

Psoriasis
A plant extract could signal a breakthrough in the treatment of a skin condition blighting the lives of one million sufferers in the UK.

Radiation sickness
Exposure to radiation can cause devastating and long-lasting damage to the body's tissues.

Radon
Radon is a gas that seeps into homes from radioactive rocks buried deep underground. If inhaled, it can cause cancer. Fortunately, it is easily dealt with.

Replantation surgery
Surgeons can implant fingers to a healthy blood supply in the arm while they treat damaged hand tissue.

Rohypnol: The date rape drug
Rohypnol is a legitimate drug used in the short-term treatment of sleep disorders, but has been abused for more sinister purposes.

Salt
Salt is an essential component of a healthy diet, but many scientists believe too much can cause serious health problems such as stroke and heart disease.

Schizophrenia
Schizophrenia is a severe and complex mental illness with a wide range of symptoms.

Self-harm
People with a history of self-harm deliberately inflict injury upon themselves, for example, by cutting or burning themselves or taking an overdose.

Sexually transmitted infections
There has been a big increase in sexually transmitted diseases. BBC News Online provides details of the most common forms.

Sickle cell anaemia
People with sickle cell anaemia should be screened for a potentially fatal complication, scientists say.

Single Sided Deafness
Single Sided Deafness (SSD) is the complete hearing loss in one ear.

Sleep disorders
Trouble sleeping is a very common problem - and there are a variety of reasons why people can't get a sound night's rest.

Smoke inhalation
Inhaling hot smoke can have a devastating effect on the delicate tissues of the respiratory system.

Smoking - the health effects
Smoking is a greater cause of death and disability than any single disease, says the World Health Organisation

Q&A: Stem cells

Sudden death syndrome
Sudden Arrhythmia Death Syndrome is a disorder of the electrical system of the heart that can lead to the death of apparently healthy people without any warning.

Tamoxifen
Tamoxifen has made a name for itself as a treatment for breast cancer. But how does it work and what are the side-effects?

Teenage drinking
Doctors are worried about an apparent increase in the number of young teenagers who are drinking heavily.

Tourette Syndrome
Tourette Syndrome is a complex and debilitating neurological disorder which is estimated to affect about 1% of the population

Tooth decay
Tooth decay is one of the most common health complaints in the world.

Tuberculosis
Health officials are struggling to contain an outbreak of TB in Leicestershire. BBC News online examines a disease which is posing a growing threat around the world.

Typhoid fever
Typhoid fever is a life-threatening illness which is common in many parts of the developing world.

Ulcerative colitis
Ulcerative colitis is one of two forms of inflammatory bowel disease, which typically affects the large bowel only.

Vibration White Finger
Vibration White Finger is one form of Raynaud's Disease which causes the extremities to turn white and become painful or numb.

Vitamin B6
More than one million people take vitamin B6 it to fight stress and increase energy. B6 is also used in conjunction with magnesium to treat autism.

West Nile Disease
West Nile Disease is a virus which is spread through the bite of an infected mosquito. Last year alone it killed over 180 people in the States.

Winter vomiting virus
The winter vomiting virus causes unpleasant but non-fatal infections that last only a few days.