none there harmless ive been bit by a few venomoid cobras and it is worse to get bit by a boa or python ,the cobras only left 2 little holes (unless they chewed)compared to 30 depending on how good a boa gets you on the other hand vipers have big fangs never got bit by a venomoid viper im sure it wouldn't feel to good . not as bad as the hot eyelash i got bit by though lol..