Liposomal lipid peroxidation and peroxide induced DNA damage were investigated. Inhibition of lipid peroxidation was studied using 400 microM uric acid, beta-carotene, alpha-tocopherol, curcumin and butylated hydroxyanisole (BHA). Curcumin, the active principle of turmeric (Curcuma longa), was as effective an antioxidant as BHA. An aqueous extract of turmeric was also found to be an effective inhibitor. The inhibition obtained using this aqueous extract, incorporated into the liposome itself, was 70% at 300 ng/microliter. This indicates the presence of yet another antioxidant in turmeric besides the lipophilic curcumin. The aqueous antioxidant extended 80% protection to DNA against peroxidative injury at 100 ng/microliter. This component of turmeric is being characterised and investigated as an antioxidant/anticlastogen and as an antipromoter.