Forty-four adult patients with various forms of dystonia were treated with anticholinergics slowly increased to maximum tolerated doses. Thirty-seven per cent of the 35 idiopathic dystonia patients had a moderate to marked improvement with an average dosage of 21.5 mg of trihexyphenidyl. Younger patients with a shorter duration of dystonia and those who tolerated higher doses tended to benefit most. However there were exceptions to all of these factors. None of the nine patients with symptomatic dystonias improved more than mildly and most had no benefit despite the use of dosages similar to those resulting in improvement in idiopathic dystonia patients. Side effects were common. These often forced drug withdrawal at lower doses than those which might have resulted in improvement. These results suggest that high dose anticholinergics should be the first line of therapy for disabling dystonia.