It specifically says it does not effect humans yet it actually does it makes you sleepy and was actually told this by my vet so think they need to change the packaging. I have used both pills and diffuser, seem to work, tho diffuser seems more effective. My dog, who is a major terrier barker, seems to be barking much much less, but we haven't used it very long, and use it off and on so I do wonder if I am hearing what I want to hear. We have been using this religiously for 6 months, our 13 year old Daxie was diagnosed with alzheimer's and cognitive problems she was crying at night getting lost and distressed in the kitchen, since plugging this in she sleeps calmly she occasionally barks but we are easily able to pacify her. Firework nights & bad weather, I think this product does work, you have to have it plugged in for at least 1 hour for it to take effect. Our 10 month old lab is not wrecking the place anymore and can be left at home on his own since we have started using the diffuser. Adaptil really helped to calm her down and life together is now lots of fun, our dog is much more relaxed, we can leave her on her own with no problems.