An hydro-alcoholic extract from Haemanthus albiflos leaves (Amaryllidaceae) was tested for its potential antiviral activity against two DNA viruses: herpes simplex virus type I, Adenovirus type 5 and three RNA viruses: poliovirus type I, vesicular stomatitis virus, simian Rotavirus SA 11. Positive results were obtained against herpes virus and all the RNA viruses tested.