Rosin is a ubiquitous contact sensitizer which may be present in dental materials such as periodontal dressings, impression materials, cements, and cavity varnishes When a hypersensitive person is exposed to a sensitizer, allergic contact dermatitis/stomatitis may develop, most commonly after direct skin/mucosa contact with the sensitizer. However, widespread dermatitis may develop after systemic administration of the sensitizer, and this paper reports the case of a rosin-hypersensitive man who developed widespread eczematous dermatitis after dental treatment with a rosin-containing product.