Bactrim is the trade name for co-trimoxazole, a combination antibiotic used to treat a variety of bacterial infections.

It consists of a mixture (co-) of the antibiotics trimethoprim (try-meth-oh-prim) and sulfamethoxazole (sulf-uh-meth-ox-uh-soul).

Bactrim is given in a variety of infections including chest infections, urine infections, and skin and wound infections. 

In the UK, in up to 1 in 3 urine infections the causative pathogens are now resistant to trimethoprim.