T.E.
The Hyland's brand is a *homeopathic* remedy. It does not actually contain the belladonna in it. It contains the energy from the plant that is obtained from putting a drop in water and shaking a certain number of times, then putting a drop of that solution in a new amount of water, shaking a certain number of times, etc. By doing this, you get the energy of the plant, but not the chemical.
I cannot explain how it is that homeopathics work, but they work.
Adding on here: Homeopaths are the safest thing you can use, because they only contain the energy from the substance. Tylenol can damage the liver (it damaged mine in only one dose) and motrin can damage the kidneys. There are no side affects from homeopaths, other than a possible allergy to the milk base that they are in to make them taste good and keep them in tiny pills.
My son got into my entire Hyland's kit when he was a baby, and ate every single one of the "pills" - that's probably over 8 bottles in the "kids kit". Nothing ever happened. He didn't seem any different, and poison control said that it wouldn't do a thing to him. That is one of the reasons I prefer to use homeopaths when I can - because they are so safe. If he would have gotten into that much tylenol, we would have been at the ER, clinging to life.