Atherosclerosis remains the major cause of death and premature disability. Hyperlipidemia is the most firmly established and best understood risk factor for atherosclerosis 1. Nowadays, major drugs used for treatment of hyperlipidemia have several adverse effects. Herbal medications such as Garlic (Allium sativum) and Anethum graveolens are prescribed as antihyperlipidemic agents.

The medicinal uses of garlic have a long history 2. Recent studies have validated many of its useful properties, such as:

• Cancer-preventive actions 345

• Stimulation of phagocytotic function of macrophages and lymphocyte proliferation 6

Antimicrobial effects. In vitro, allicin, the main organosulfur compound of garlic, has demonstrated activity against gram-positive and gram-negative bacteria as well as fungi, protozoa, and certain viruses 7.

• The cardiovascular-protective effects of garlic have been evaluated extensively in recent years. In animal experiments, garlic extracts have been shown to lower plasma lipid and cholesterol in rats [89, and 10], rabbits 11, chickens 12, and swine 13. Moreover, a number of intervention studies have similarly shown that garlic significantly reduced plasma lipids, especially total cholesterol and Low Density Lipoprotein (LDL) cholesterol in humans [1415, and 16]. Aside from the reported antiplatelet aggregation and antithrombotic action 17, garlic reduced blood pressure [1819, and 20] and stimulated fibrinolytic activity 2123. It was reviewed that aged garlic extract contains antioxidant compounds and increase nitric oxide production and decreases the output of inflammatory cytokines from cultured cells. These data suggest that garlic may improve impaired endothelial function in men with coronary disease treated with aspirin and statin 22. Two meta-analyses of randomized, placebo-controlled human studies confirmed the hypocholesterolemic effects of garlic 2425. The analyses further detected that the extent of the cholesterol-lowering properties of garlic differed markedly from one study to another 2425. It was estimated from the five randomized clinical trials that hypercholesterolemic patients treated with garlic had a mean plasma cholesterol concentration that was 9% lower than that of patients treated with placebo 25. Silagy and Neil 25, on the other hand, concluded from the analysis of 17 human studies that plasma cholesterol concentrations of the subjects treated with garlic were 12% lower than those receiving placebo. Furthermore, the two analyses detected a wide range of decrease in mean plasma cholesterol concentrations (i.e., 6–53 mg/dl) among the studies. However, garlic supplementation has been shown not to decrease plasma cholesterol concentrations in human [2627, and 28]. Although the reasons for the inconsistent observations are not readily apparent, it is worthwhile to note that garlic contains a variety of organosulfur compounds, amino acids, vitamins and minerals 2. Some of the sulfur compounds such as allicin, ajoene, S-allylycysteine (SAC), diallyl disulfide (DADS), S-methylcysteine sulfoxide, and S-allylcysteine sulfoxide may be responsible for the therapeutic properties of garlic 9. Animal studies have shown that garlic supplementation in the diet depressed the hepatic activities of lipogenic and cholesterogenic enzymes such as 3-hydroxy-3-methyl-glutaryl-CoA(HMG-CoA) reductase 29.

Anethum graveolens is another herbal medication with antihyperlipidemic effects. Administration of water extract of anethum graveolens leaves for 14 days can reduce triglyceride and total cholesterol levels by almost 50 % and 20 %, respectively 30.

Nowadays, there is wide spread belief among general public that garlic and anethum graveolens have beneficial effects on hyperlipidemia. This belief persuaded us to perform this investigation.

A single-blind, randomized, placebo-controlled intervention study was conducted on patients with coronary artery disease with newly diagnosed hyperlipidemia. One hundred and seventy two patients were selected from cardiology outpatient department of Shiraz University of Medical Sciences. Exclusion criteria included; having significant hepatic, renal and gastrointestinal tract disease, acute myocardial infarction, uncontrolled endocrine disease, and underlying previous therapies for hyperlipidemia. Twenty two cases were excluded. One hundred and fifty patients had total cholesterol level ≥ 200 mg/dl and/or LDL-cholesterol ≥ 100 mg/dl after 10 hours of fasting with standard enzymatic methods. Also, we checked HDL-cholesterol and triglyceride. Written informed consent was obtained from each patient before any study-specific procedure.

We randomly divided patients into three groups, each composing of 50 cases. Garlic group received enteric-coated garlic powder tablet (equal to 400 mg garlic and 1 mg allicin) twice daily. Patients of Anethum group were prescribed anethum tablet 650 mg twice daily. Placebo group were given placebo. Demographic information of different groups is in table 1. After 6 weeks, we checked total cholesterol, LDL-cholesterol, HDL-cholesterol, and triglyceride after 10 hours of fasting.

All patients were given NCEP type Π, i.e. protein about 0.6 g/kg desirable body weight per day, 55 % of total calories from carbohydrate, no more than 30 % of total energy intake be derived from dietary fat, polyunsaturated fats to <10 %, saturated fat & trans-fat should be limited to <10 % of calories, throughout the study.

Data were analyzed by paired sample t test and non parameter 2 related sample test using SPSS 13.0 program for windows (SPSS Inc. Chicago, Illinois). A difference was considered statistically significant when the probability value (P-value) was < 0.05.

Fortunately, all of the patients cooperated well and did not show any adverse effect of these herbal drugs.

Changes of lipid profiles after 6 weeks and results of paired t test are shown in table 2 and 3, respectively. It was found that changes in triglyceride, total cholesterol, LDL-cholesterol, and HDL-cholesterol were significantly different between three groups.