Extracts of twelve medicinal polyherbal preparations in powder form sold at retail shops were tested for mutagenicity using Ames in vitro test. Five of the polyherbal preparations were found to be mutagenic (p ≤ 0.05) at 250 μg/ml. Two mutagenic preparations comprised of traditionally used medicinal plants with no mutagenicity property being reported. However, one polyherbal preparation which contained one mutagenic plant was found not mutagenic. Under the conditions of this study, it can be concluded that some polyherbal preparations were potentially mutagenic and mutagenicity of polyherbal preparation cannot always be deduced from the mutagenicity status of each individual plant components of the polyherbal preparations.