We studied the effect of adding low-dose bromocriptine to levodopa/carbidopa (Sinemet) in 26 patients suffering from progressive Parkinson's disease with loss of levodopa effectiveness or levodopa-induced fluctuations. Despite the high incidence of drug intolerance and low response rates, a significant proportion of patients with the wearing-off effect and dystonia improved. Low-dose, slow-increase bromocriptine is warranted as adjunctive therapy in these patient subgroups.