The present invention relates to non-psychoactive derivatives of tetrahydrocannabinol, which are useful in treating interstitial cystitis and relieving symptoms thereof. The invention uses (6aR,10aR)-Δ8-tetrahydrocannabinol-11-oic acids (hereinafter referred to as (6aR,10aR)-Δ8-THC-11-oic acid), as well as pharmaceutical compositions containing the (6aR,10aR)-Δ8-THC-11-oic acids, for treatment of interstitial cystitis in a mammal. The invention further covers methods of formulating and administering the compounds and pharmaceutical compositions as therapeutic agents in the treatment of interstitial cystitis, with particularly preferred administration routes being oral and via intravesicular instillation.
