I always wondered this when buying $1 body wash at Dollar General:

Last year, New York magazine investigated how thieves were stealing laundry detergent to sell for drug money. One Safeway reported losing up to $15,000 a month in stolen detergent. Who would have expected the city’s underground economy to intersect with its legitimate economy thanks to such utterly boring products? [Priceonomics]

via Why Do Drug Stores Put Soap Under Lock and Key?.

Body Washes, soaps and clothing detergent are all being secured in stores now.