Sulphanilamide molecule. Molecular model of sulphanilamide (C6H8N2O2S), also known as 4- aminobenzenesulphonamide. Carbon atoms are black, hydrogen are white, nitrogen are blue, oxygen are red and sulphur is yellow. Sulphanilamide forms colourless crystals. It is used as a treatment for bacterial infections, for example streptococcal infection and meningococcal meningitis. It is bacteriostatic rather than bactericidal. This means that the drug stops the growth of bacteria, thereby allowing the body's own defence mechanisms to destroy the bacteria.