The effects of acetic acid fermented juice prepared with submerged culture media of Antrodia camphorata mycelium (AJA: pH 3.2, acidity 2.0, Brix degree 3.2) on blood glucose levels and serum lipid profiles of rats in which diabetes was induced with streptozotocin (STZ) were investigated. Rats were divided into normal controls (NC), diabetic controls (DM), and groups receiving diluted (1:1, with water) AJA (A1) and undiluted AJA (A2). The volume of liquid given to both A1 and A2 animals was 0.5 mL/100 g body weight. In the A1 and A2 groups, compared with the DM group, polyphagia, liver enlargement, and weight loss caused by diabetes were considerably alleviated, but did not attain the levels of NC group rats. In the A1 and A2 groups, the levels of blood glucose were 17.1% and 28.2% lower than in the DM group. There was no significant difference in the levels of fructosamine between the DM and A1 group, but the A2 group had a level 16.3% lower than the DM group. In the A1 and A2 groups, compared with the DM group, serum triglyceride levels decreased by 44.1-48.0%, serum total cholesterol by 24.0-31.1%, and serum LDL-cholesterol by 25.2-51.1%. The level of HDL-cholesterol in A2 animals rose by 45.9% compared to NC rats. The results show that AJA may be a useful beverage for diabetes patients, offering both antihyperglycemic activity and improvement in levels of serum lipids.