Mahkota Dewa (Phaleria macrocarpa (Scheff.) Boerl.) have used by traditional healers to treat diabetes patients, but there is no clinical evident to prove its safety and efficacy. This was a clinical observation study 17 diabetes patients who treated using raw extract of Mahkota Dewa fruit in capsule preparation have been observed for 4 (four) week in the year of 2005 The diabetes treatment of as the study aimed to determine the safety and the efficacy of Mahkota Dewa (Phaleria macrocarpa (Scheff.) Boerf.) to decrease the blood glucose titers in Diabetes Mellitus (OM) patients. It was a clinical observation study. The clinical observation were conducted to 17 OM patients treated with extract of the Mahkota Dewa fruit in capsule preparation the same as therapy procedures by the traditional healers at traditional clinics in Surabaya year 2005. The OM patients were given the therapy as follows: at the 1st week: 1 time x 1 capsule, at the 2nd week: 2 times x1 capsule, at the 3rd and 4th week: 3 times x 1 capsule per day. Anamnesis, the physical and laboratory evaluations were conducted at visit in every week. Results showed that the therapy with Mahkota Dewa extract for 4 (four) weeks is not effective to decrease the blood glucose. Only 1,5.9%, patient with Diabetes Mellitus become normal blood glucose at the end of the therapy. The laboratory results of liver (SGOT, SGPT) and kidney (BUN, creatinin serum) functions showed that the Mahkota Dewa capsules were safe for 4 (four) weeks consumption, no toxicity effects for the liver and kidney. Furthermore the SGOT and SGPT tended to decrease. It recommended not to use the Mahkota Dewa extract as a single therapy to treat OM patients because of the unproven efficacy.