Being a marketing manager in desiccant production company, I get so many mails from clients regarding inquiries about silica gel and oxygen absorber products. I remember once a lady called me and she was very scared. She told me that her yorkie was chewing something, she checked and found that that packet what her yorkie eating was actually a silica gel packet with the print "Not to be eaten". She sent me a pic of that pack which you can find below.
http://imgur.com/GtSu5Mt
She wanted to know, is that packet Poisonous To Dogs? I simply told her no need to worry about it, as the
silica gel sachets are completely non toxic material and most dogs get away with this. It's better to keep and eye on your dog and if you see any odd symptoms, you should contact your nearest pet doctor. This little packets, commonly marked "Not to Eat" so people think such pockets might be poisonous.