1949-1990

1949-1955: The stress of playing volleyball several hours a day and studying at night lands him in hospital, but he ignores doctors' warnings and discharges himself.

1987: Taken to hospital with head and heart pains shortly after his dismissal from the Soviet Communist Party Politburo.

1990

Boris Yeltsin in 1988

March 1990: Suffers from heart problems during a Communist Party Central Committee meeting just after being elected as a member of parliament.

April 1990:Undergoes operation in Barcelona, Spain, for a slipped disc.

1991

September 1991: Forced to take a break due to minor heart problems, following the putsch that made him the most high-profile champion of democracy in the Soviet Union.

October 1991: Ordered to take two weeks' rest after aides said he suffered minor heart problems.

1992

Boris Yeltsin shares a drink with George Bush in June 1992

January 1992: Fails to meet Japan's Foreign Minister. Aides say he has a heart condition but he reappears in good spirits 24 hours later.

April 1992: Misses a meeting with the then US Treasury Secretary Nicholas Brady. He claims he was working, but media say he was drunk.

1993

April 1993: Says he has only two problems - tiredness and lack of sleep.

September 1993: Suffering back pains, he invites the Spanish surgeon who operated on him in 1990 to Moscow.

1994

Boris Yeltsin and Bill Clinton in September 1994

February 1994: Catches a "cold" that keeps him away from Moscow for two weeks in the midst of the Bosnia crisis.

April 1994: Offers to undergo a public check-up, adding: "I hope you will all be as well as I am when you reach my age."

September 1994: Fails to get off the plane during stopover at Shannon airport in Ireland, keeping the Irish Prime Minister waiting on the tarmac. Russian officials say he has "forgotten" to wake up, but his former bodyguard says he suffered more heart trouble.

December 1994: Admitted to hospital for 10 days for what is officially described as a nose operation, just as Russian troops pour into Chechnya.

1995

April 1995: Spokesman says he suffers from high blood pressure.

July 1995: Hospitalised for a fortnight with an ischaemic heart condition - a blood supply problem. A photograph is released to show he is well, but is later revealed to bear a suspicious resemblence to a picture taken in April.

October 1995: Hospitalised for a month with more circulatory and heart problems.

1996

February 1996: Launches a vigorous campaign to win a second term in office. Travels non-stop, holds dozens of meetings and even dances the twist.

In hospital in 1996

June 1996: Disappears from public a week before the end of the election campaign, officially due to sore throat and fatigue. Later it emerges that he has suffered another heart attack.

3 July, 1996: Re-elected president.

15 July, 1996: Welcomes US Vice-President Al Gore at a government rest home in the Moscow suburbs, in the presence of a doctor.

August 1996: An aide says the president is suffering from "colossal weariness" after his election campaign and needs two months of peace and quiet.

September 1996: Breaks with Kremlin tradition to say he will have heart surgery.

20 September, 1996: Chief heart specialist Renat Akchurin tells a US television channel Yeltsin had an unreported heart attack in late June or early July.

November 1996: Undergoes successful quintuple heart bypass operation in the Central Clinical Hospital in Moscow.

December, 1996: Returns to Kremlin.

1997

9 January, 1997: Hospitalised for double pneumonia until January 20.

February 1997: Resumes work in the Kremlin.

March 1997: First foreign trip after the operation and illness. Meets US President Bill Clinton in Helsinki.

July 1997: Regains some of the weight he lost during his illness. He says his heart "works like a clock".

4 November, 1997: Akchurin says Yeltsin's latest medical check-up shows he was in good health.

10 December, 1997: Admitted to hospital with a viral infection.

1998

13 January, 1998: Rides a snowmobile to demonstrate his fitness.

The Black Sea residence where Mr Yeltsin has spent time recuperating

10 March, 1998: Yeltsin claims his doctors have pronounced him fit and well. He says journalists are too concerned about his health and challenged reporters to beat him at a sport of their choice.

13 March, 1998: Respiratory infection forces Yeltsin to cancel appointments.

17 March, 1998: Moscow announces postponement of summit meeting of leaders of former Soviet states due to have been held on March 19, after Yeltsin's doctors order further rest to allow him to recover from respiratory infection.

20 March, 1998: Returns to work in the Kremlin.

28 April, 1998: French President Jacques Chirac is quoted saying that Yeltsin's health is good, but he has had a liver problem and is abstaining from alcohol.

3 September, 1998: At a news conference with Clinton, Yeltsin has trouble remembering protocol. He shocks his audience by leaving a long pause before giving an oblique reply to a question on former premier Victor Chernomyrdin.

8-9 October, 1998: Looks pale, speaks with difficulty and walks stiffly at a Kremlin meeting with Palestinian leader Yasser Arafat.

Mr Yeltsin stumbles during a visit to Uzbekistan

11 October, 1998: A ceremony welcoming the president to Uzbekistan, is cut short after he appears to stumble. He is supported by Uzbek President Islam Karimov. Aides say he is suffering from a cold and cough.

12 October, 1998: Suffers a prolonged bout of coughing at a signing ceremony in Uzbekistan.

27 October, 1998:Checks into a sanatorium - a day after abruptly calling off his visit to Vienna suffering from "unstable blood pressure".

29 October, 1998: Gives up day-to-day running of the country. Deputy Chief of Staff, Oleg Sysuyev, announces the president will concentrate on revising the constitution to ensure a stable transition to his successor.

18 November, 1998: Cancels trip to India - no official explanation given.

23 November, 1998: Readmitted to hospital with what the Kremlin says is a bout of pneumonia, after developing a high temperature. Talks with visiting Chinese President Jiang Zemin are switched to the Central Clinical Hospital in Moscow, where the two leaders are shown looking relaxed.

7 December, 1998: After a brief return to the Kremlin, President Yeltsin is back in hospital again, having sacked one of his closest advisers.

1999

17 January, 1999: President Yeltsin is taken to hospital to be treated for an acute stomach ulcer.

8 February, 1999: The president flies back to Moscow hours after arriving in Amman for King Hussein's funeral. His aides deny Jordanian reports that he needed medical attention.

27 February, 1999: Returns to hospital where examination shows he needs further treatment for his ulcer. He is not released until three weeks later.

18 May, 1999: A spokesman denies reports that President Yeltsin is ill with bronchitis after he cancels a meeting with the Spanish prime minister.