This review provides assessments of the efficacy and safety of oral forms of phytotherapy in psoriasis management and discusses the pharmacological actions of the plants that have been frequently used in clinical trials. It employed the methods described in the Cochrane Handbook. Ten randomized controlled trials that compared a plant-based intervention with placebo or a pharmacotherapy in the treatment of psoriasis vulgaris and used Psoriasis Area Severity Index (PASI) as an outcome measure were included. Superiority to placebo was found in two out of three studies. In six out of seven studies, the effect of the phytotherapy was reported as comparable to the pharmacotherapy in the short term when assessed as PASI 50. The safety of the phytotherapies was discussed. The most commonly used plants were Oldenlandia diffusa, Rehmannia glutinosa and Salvia miltiorrhiza. Experimental studies on extracts and compounds derived from these plants have reported anti-inflammatory, anti-proliferative and other actions of relevance to psoriasis management. These properties may account for the apparent actions of some of the phytotherapies used in these clinical studies. These plants and their active constituents appear to warrant further research attention in the search for future medications for psoriasis.