As a beta-lactam, its bactericidal activity results from the inhibition of cell wall synthesis via affinity for penicillin-binding proteins.

[2] Side effects include nausea and vomiting, diarrhoea, hypersensitivity reactions, nephrotoxicity, convulsions, CNS toxicity, hepatic dysfunction, haematologic disorders, pain at injection site, thrombophlebitis, pseudomembranous colitis, and superinfection with prolonged use.

It has similar or less activity against Gram-positive staphylococci and streptococci, but is resistant to some beta-lactamases produced by Gram-negative bacteria.

It is more active against many of the Enterobacteriaceae including Enterobacter, E. coli, Klebsiella, Salmonella and indole-positive Proteus species.

[citation needed] In clinical use, high concentrations of cefotiam are observed in several tissues (kidney, heart, ear, prostate, and genital tract), as well as in fluids and secretions (bile, ascitic fluid).