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At present , inhibitors from snake serum and plasma , several synthetic compounds and their analogs have been demonstrated to possess anti - snake venom activities , but the use of plant metabolites for this purpose has an added advantage of traditional knowledge and will make the treatment cheaper and more accessible to the affected population .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None