NHS information on how to deal with rashes in babies and children, such as chickenpox, eczema, impetigo, ringworm, scabies, slapped cheek syndrome and more.
Find out why you might need to have a red blood cell (RBC) count and what the results could indicate.
Find out when to get medical advice if you have a red eye, and read about the most common causes.
Find out about reflux, where a baby brings up milk during or soon after a feed.
Find out more about the different types of lower and upper respiratory tract infections (RTIs) (airway infections), how the infections spread and when you should see a GP.
Read about a retinal migraine (ocular migraine), an eye condition that causes brief episodes of blindness or visual problems like flashing lights in 1 eye.
Find out about retinoblastoma, including the signs and symptoms, what causes it, how it's diagnosed and treated and when screening is recommended.
Read about Rett syndrome, a rare genetic disorder that affects brain development and causes severe physical and mental disability from early childhood.
Read about Reye's syndrome, a rare disorder that can cause liver and brain damage. If Reye's syndrome is not treated promptly, it can be fatal or result in permanent brain injury.
Find out about the childhood infection roseola, including what the symptoms are, how to treat it and when to get medical advice.
Find out what rabies is, how it's spread, the rabies vaccination and what to do in an emergency.
Find out about radiotherapy, including what it is, how it works, when it's used, how it's given and the possible side effects.
Find out about Raynaud's phenomenon, a common condition that affects the blood supply to certain parts of the body, usually the fingers and toes.
Reactive arthritis is a condition that causes inflammation (redness and swelling) in various places in the body.
A rectal examination is where a doctor or nurse inserts a finger into your bottom (rectum) to feel for abnormalities. Find out why it's needed and what happens before, during and after the procedure.
Repetitive strain injury (RSI) is a general term used to describe the pain felt in muscles, nerves and tendons caused by repetitive movement and overuse. Find out what causes RSI and how to treat and prevent it.
Find out what restless legs syndrome (RLS) is, what causes it, and how it can be treated.
Read more about restricted growth, sometimes known as dwarfism, a condition characterised by short stature.
Rhesus disease (haemolytic disease of the foetus and newborn) is a condition where antibodies in a pregnant woman’s blood destroy her baby's blood cells
NHS information about rheumatic fever, including treatment, symptoms and causes.
Read about rheumatoid arthritis, a long-term condition that causes pain, swelling and stiffness in the joints.
Rickets is a condition that affects bone development in children. It causes the bones to become soft and weak, which can lead to bone deformities.
Find out about what happens in root canal treatment, including how it's performed, how long it takes and how successful it is.
Rosacea is a common long-term skin condition that mainly affects the face. It's more common in women, but can be worse in men. It can get worse if it's not treated.
Rubella (german measles) is a viral infection that's now rare in the UK. It's usually a mild condition.
Ringworm is a fungal infection that causes a rash. Find out about the symptoms and how it can be treated.