The antiviral activities of sodium dichloroisocyanurate (NaDCC) and a commercial product (Solprogel 2%) against human immunodeficiency virus type 1 (HIV-1) were investigated using a quantitative suspension test method. Solprogel is a compound that contains NaDCC and a biodegradable polymer of acrylic acid. Viral suspensions were prepared containing 3.2 x 10(6) tissue culture infective dose 50 (TCID50) in culture media. Syncytium formation in the MT-2 line and HIV antigen p24 on the supernatant of the cultures were used to determine viral titre. Results indicate that satisfactory disinfection (1000-fold reduction in 5 min) can be achieved using NaDCC and Solprogel at concentrations of 100 and 120 ppm available chlorine, respectively.