Although Juniperus phoenicea L is a widely distributed wild tree in the south of Saudi Arabia, but its phytochemical and physiological evaluation is still poor. The chromatographic separation of the CH2Cl2/MeOH, 1:1 extract of J, phoenicea L. fruits gave ?-sitosterol, stigmasterol, four labdane and two pimarane diterpenoids, including new labdane diterpenoid. Additionally, the volatile compounds of the main petroleum ether extract, as well as the steam-volatile constituents were identified by GC/MS. The separated compounds were identified by spectral tools. The new diterpenoid was identified as 5,9,10-triepicupressic acid. A previous false identification of sandracopimaric acid, from the fruits of Juniperus phoenicea L. grown in Egypt, was detected and declared to be revised. Total antioxidant capacity of extracts was estimated using total antioxidant capacity kit of Biodiagnostic, based on Koracevic et al., for biological fluids, with slight modification to suit extracts. Ascorbic acid was used as a reference antioxidant compound. Reasonable results were obtained by applying the modified method on petroleum ether extract, methylene chloride extract and ethyl acetate extract of Juniperus phoenicea L.