Transdermal compositions containing castor oil are described. The compositions comprise ricinoleic acid and a transdermal vehicle with optional additional agents. One optional additional agent is an adrenergic drug which may cause the ricinoleic acid to penetrate the skin more deeply and have a longer lasting effect. The compositions can be used for treating a variety of ailments traditionally treated with castor oil or castor oil packs, without the mess and inconvenience of using castor oil packs.