Two patients with psoriasis vulgaris who travelled to endemic malaria areas developed erythroderma and generalized psoriasis guttata 3-4 weeks after starting prophylactic antimalarial medication with chloroquine/proguanil. The lesions resolved after 3 months of intensive treatment and discontinuation of the antimalarial drugs. The literature on these less known adverse effects of antimalarials in psoriatic patients is reviewed. Because of the severity of a malaria infection we advise psoriasis patients to have adequate malaria prophylaxis.