Do not run a race if you feel unwell or have recently been unwell within 2-3 days of the race, even if you are raising money for charity. Most medical emergencies during races occur in runners who were unwell before the race, but didn't want to miss the event. If you've had a fever or vomiting or diarrhoea or chest pains, or otherwise feel unwell, then it is unfair to you, your family, your sponsoring charity and the race support staff to risk serious illness and become a medical emergency. You are unlikely to do yourself justice, and there are many other races that you will be able to compete in when you feel better.
Medicines, Supplements and Drugs
Taking part in an endurance event is not the time to experiment with over the counter medication, supplements or recreational drugs.