Drug induced erythema multiforme (EM) is a rare clinical entity which majorly involves the oral cavity. It commonly occurs due to intake of drugs such as NSAID'S, certain antibiotics, and anticonvulsants. It is characterized by rapidly rupturing vesicles leading to ill-defined erosions in the oral cavity and encrusted lip lesions. These lesions are usually difficult to differentiate from other vesiculo bullous and ulcerative lesions which would have a similar presentation and the absence of skin lesions can sometimes lead to misdiagnosis. Drug induced EM has an acute onset and is a self-limiting inflammatory hypersensitivity reaction that causes blistering and ulcerations of the skin and mucous membrane. The lesions heal following the discontinuation of the causative medications. This case report describes a case of drug induced erythema multiforme of the oral cavity that occurred consequent to the intake of Tab.Diclofenac Sodium and Tab.Cephelexin. The patient developed painful, bleeding, burning ulcerations with severe crustations on the upper, and lower lip, lateral and ventral surface of tongue, hard palate and retro molar regions. The case was managed with corticosteroids.