It will give you diarrhea if you swallow it, because soap is an efficient laxative. Some antibacterial brands contain triclosan, which is said to react with chlorine in tap water to form chloroform, a carcinogen; however, the amount that results is less than the amount of chloroform already present in chlorinated tap water. In the presence of ultraviolet light (which one rarely encounters inside the bathroom), triclosan can degrade to form dioxin; be aware, though, that dioxin is not one compound but a family of compounds, only 17 of which are of concern in human health — and the one formed by triclosan is not a public health concern. However, byproducts of triclosan formed in surface water as a result of exposure to sunlight present a number of environmental concerns. For this reason, in the U.S. products containing triclosan (which include certain toothpastes, Clearasil, Softsoap, Dial, Right Guard, Old Spice, & Bath and Body Works hand sanitizers, among others) are required to say so on the label. To avoid this chemical, simply read the label.

Dishwasher detergent, on the other hand, is extremely toxic. Care should be exercised in using it: don’t use it in the sink to wash dishes. If you get it on your skin, wash it off immediately. Store dishwasher detergent out of reach of small children, and watch the dishwasher cup. If dishwasher detergent accumulates in it, as will happen when the machine isn’t running optimally, be very careful that curious small children don’t mess with it. If a child puts any of it in his or her mouth, call poison control and get the kid to an ER immediately.

Good luck!