Find out about febrile seizures (febrile convulsions or fits), which can sometimes happen when a child has a high temperature (fever).
Find out what female genital mutilation (FGM) is, why and where it's carried out, what the health risks are, and where to get help and advice.
Find out about flat feet (fallen arches), including why they happen, whether they're serious and how they can be treated.
Read about fluoride – a naturally occurring mineral that is added to toothpaste, drinking water and some foods, which can help prevent tooth decay.
Find out about foetal alcohol spectrum disorder, which is a range of mental and physical problems that can affect a child if their mother drinks alcohol while pregnant.
Find out about the possible link between some artificial food colours and hyperactivity in children.
NHS information about food intolerance, including symptoms, diagnosis and treatment.
Find out about foot drop, where it's difficult to lift or move your foot and toes when walking.
Find out more about fainting (syncope), when you pass out for a short time.
Anyone can have a fall, but older people are more vulnerable and likely to fall, especially if they have a long-term health condition.
Find out about femoral hernias, a rare type of hernia.
Read about the different types of fibroids and why they develop. Find out when to see a GP if you have fibroids and how they're treated.
Fibromyalgia, also called fibromyalgia syndrome (FMS), is a long-term condition that causes pain all over the body.
Find out what to do in emergency situations such as anaphylaxis, bleeding, burns and scalds, choking, drowning, electrocution, fractures, heart attacks, poisoning, shock and stroke.
Flatulence is passing gas from the digestive system out of the back passage. It's more commonly known as "passing wind", or "farting".
NHS information about flu, including symptoms, how to treat it yourself and when to get help.
Find out more about food allergies, including what the symptoms are, what can cause them and how they're treated.
Read about the symptoms and causes of food poisoning and what you should do if you get it. It's not usually serious and most people get better within a week without treatment.
Find out what frontotemporal dementia is, what the symptoms are, how it's treated, and what the outlook is.
Read about frostbite, how it's caused and how to prevent it. Also find out what to do if you have frostbite and when to get medical assistance.
Frozen shoulder means your shoulder is painful and stiff for months, sometimes years. Find out about the main symptoms, treatments and causes.
NHS information about fungal nail infections, including symptoms, self-care, when to get medical help, treatments and prevention.
Find out about floaters, which are small shapes that some people see floating in their field of vision.
Feeling sick (nausea) is common and usually goes away on its own. Find out about some things you can try that might help and what might be causing it.
Get information and advice about different types of foot pain, including ankle pain, heel pain and toe pain.
Find out what to do about finger pain, when to get help and the common causes.
Find out about fabricated or induced illness (FII), which is a rare form of child abuse where a parent or carer exaggerates or deliberately causes symptoms of illness in the child.
Find out how female sterilisation (also called “getting your tubes tied” or tubal ligation) works to prevent pregnancy, how it’s done and what to expect after surgery.
Find out about the flu vaccine, including who should have it, how to get it and side effects.