Cannabi­noids have been found to have antiox­i­dant prop­er­ties, unre­lated to NMDA recep­tor antag­o­nism. This new found prop­erty makes cannabi­noids use­ful in the treat­ment and pro­phy­laxis of wide vari­ety of oxi­da­tion asso­ci­ated dis­eases, such as ischemic, age-related, inflam­ma­tory and autoim­mune dis­eases. The cannabi­noids are found to have par­tic­u­lar appli­ca­tion as neu­ro­pro­tec­tants, for exam­ple in lim­it­ing neu­ro­log­i­cal dam­age fol­low­ing ischemic insults, such as stroke and trauma, or in the treat­ment of neu­rode­gen­er­a­tive dis­eases, such as Alzheimer’s dis­ease, Parkinson’s dis­ease and HIV demen­tia. Nonpsy­choac­tive cannabi­noids, such as cannabidoil, are par­tic­u­larly advan­ta­geous to use because they avoid tox­i­c­ity that is encoun­tered with psy­choac­tive cannabi­noids at high doses use­ful in the method of the present inven­tion. A par­tic­u­lar dis­closed class of cannabi­noids use­ful as neu­ro­pro­tec­tive antiox­i­dants is for­mula (I) wherein the R group is inde­pen­dently selected from the group con­sist­ing of H, CH.sub.3, and COCH.sub.3. ##STR1##