Background: Anorexia and cachexia are one of the major problems in patients suffering from advanced malignancies. Objectives: This study aimed at evaluating the efficacy of herbal combination containing Fenugreek, Fennel, and Chicory supplementation to the high-dose megestrol for the treatment of cancer-induced cachexia and anorexia. Methods: This quasi-experimental study was performed on 47 adult patients with advanced malignancy; they experienced anorexia and weight loss over the 2 past months and referred to a university-affiliated hospital (Omid) in Isfahan, Iran. Patients who had met the inclusion criteria were assigned to take either herbal combination or placebo tablets in addition to megestrol (160 mg daily) for a 2-month follow-up. All patients’ demographic information, weight changes, anthropometric indices, as well as the quality of life criteria were recorded at the baseline and after the duration of follow-up. Results: Patients in the herbal combination group experienced a mean weight gain of 1.5 kg, while patients in the placebo group had an average weight loss of 0.6 kg. Anthropometric indices including triceps skinfold thickness, mid-arm muscle circumference index, and grip strength were significantly improved in the herbal combination group. The other evaluated criteria such as quality of life, functional assessment of anorexia/cachexia therapy (FAACT), and some factors of Anderson criteria were significantly improved in the herbal combination group than the placebo group. Conclusions: Given the ameliorated results of the herbal combination supplementation in terms of weight gain and appetite improvement, as well as physical and quality of life enhancement, it seems that the herbal combination can be used as an adjunctive treatment for the management of patients suffering from cancer-induced cachexia and anorexia.