Women who swap hormone replacement therapy for alternative therapies to treat menopause symptoms risk harming themselves, doctors say.
Some women are using alternative therapies instead of HRT
The Royal College of Obstetricians and Gynaecologists also warned women not to expect too much from the therapies.
They said there was some evidence they reduced hot flushes, but there was also a risk of stomach upset and rashes.
In one case, a woman even needed a liver transplant after taking the herb black cohosh.
HRT is the traditional medical treatment used to relieve the symptoms of the menopause, including hot flushes and mood swings.
But it also increases the risk of stroke, breast cancer, heart disease, or developing a blood clot on the lungs.
The guidance from the college examines complementary therapies and their effectiveness in clinical studies.
Over 200 remedies exist, although valuable scientific research has only been conducted on a few.
About 40% of women seeking treatment for the menopause are estimated to use alternative therapies alongside of or instead of HRT.
The paper said the overall effectiveness of alternative preparations indicates a 50-60% reduction in symptoms, compared to traditional HRT which has 80-90% reduction in symptoms.
It said some of the better researched therapies such as red clover and soy had been shown to be beneficial in treating symptoms, but there was conflicting evidence over others.
In particular, it said some products could carry a slight risk of minor, transient adverse events, such as gastrointestinal upsets and rashes".
And it added in one case, a woman using black cohosh needed a liver transplantation after a particularly severe reaction.
The college said while causality was not proven, doctors had been told about the case.
Richard Warren, honorary secretary of the RCOG, said: "The current interest and enthusiasm directed towards alternative treatments for menopausal symptoms is understandable, but the full risks and benefits of these alternatives are still unknown.
"Each case needs to be considered individually. In women with specific risk factors, a clinician should weigh up the advantages and disadvantages of alternative therapies compared to those of traditional HRT.
"Interactions with commonly used medications such as warfarin and anti-depressants can cause potentially fatal results."
A spokesman for Prince Charles' Foundation for Integrated Health, which was set up to promote the use of complementary medicine in mainstream health care, admitted more research was needed into such therapies.
"Our view is that we support the report that more research needs to be done."