We treated five patients with intractable sympathetic ophthalmia and six patients with severe Behçet's disease by high-dose, short-term chlorambucil therapy. We used a total dose ranging from 306 mg to 4.2 g and a duration of therapy no longer than 36 weeks and in most cases less than 24 weeks. After termination of therapy all 11 patients had a sustained remission of their eye disease. Unless subretinal neovascularisation was present, all had a final visual acuity of 20/50 or better. Malignancy has not developed in any of our cases, with a follow-up ranging from 6 months to 12 years (mean, 4.5 years). Although 30- and 40-year follow-ups and larger numbers of patients may be necessary fully to realise the risks of chlorambucil, we believe that our high-dose, short-term regimen (Behçet's disease: average duration, 23 weeks; average total dose 2.2 g; sympathetic ophthalmia: average duration, 11 weeks; total average dose, 0.9 g) may be safer than previously reported chlorambucil regimens of one to two years or longer. In addition we fulfilled our aim of discontinuing all concomitant systemic corticosteroids within a relatively short time (usually six to eight weeks).