Mushrooms are macrofungi widely consumed as food. However, many mushrooms rot away in the wild because of fear of toxicity. Therefore, lyophilized aqueous extracts of 6 mushroom species collected from Zaria, Nigeria and taxonomically identified as Chlorophyllum molybdites, Panaeolus subalteatus, Macrolepiota procera, Leucopaxillus albissmus, Hygrophoropsis aurantiacus and Pholiota aurea were screened for toxicity in mice. Lyophilized aqueous extract of each of these mushrooms was administered to three groups of 3 mice intraperitoneally (i.p.) at doses of 100, 1000 and 10, 000 mg kg-1, respectively. Another group of three mice given distilled water served as control. The mice were examined for clinical signs of toxicity over a period of 72 h and pathological examinations conducted on dead animals. The severity of clinical signs, onset of death and pathological lesions were dose dependent. Death occurred within 10 min in all the mice dosed at 10,000 mg kg-1 with the lyophilized extracts of all the mushrooms screened, with the exception of that of H. aurantiacus, which produced death 21-23 h post administration. This result showed that all the screened mushrooms, including the popular edible M. procera were found toxic. Therefore, since all the mushrooms screened were found toxic, it is recommended that extreme caution should be exercised in their consumption. Furthermore, in view of the regional differences in the toxicity of mushrooms, there is the need to screen more wild mushrooms found in Nigeria for toxicity. This will boost mushroom mycophagy, reduce poisoning incidence and reduce wastage of edible mushrooms in the wild.
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