Boswellic acids (BAs), the main biologically active compound of frankincense, are orally available and known to exhibit anti-inflammatory activities. This is a Phase IIa bicentric baseline-to-treatment study with the standardized frankincense extract Boswelan to test the safety, tolerability and efficacy of BAs in RR-MS patients. Following a 3-month screening phase, patients received an individualized dose finding identifying the highest well tolerated BOSWELAN dose for each patient. The primary outcome in the treatment phase (Stage 3) will first compare mean Gd-enhancing lesion number occurring during the 4 month baseline to mean Gd-enhancing lesion number occurring months 5, 6, 7, 8 on treatment in patients treated with a dose of at least 800 mg t.i.d.