Lye bar soap has been used for hundreds of years for cleaning and washing. In times past, lye soap was made once a year when hogs were slaughtered to prepare for winter. The fat, or lard, was combined with lye and made into bars of soap. However, modern lye soap can be made at any time, and lard is optional.

Lye bar soap was first made by Muslim chemists in medieval times. The soaps made in this time were not the lye soap we are familiar with today. They were a mixture of vegetable oils, aromatic oils and lye boiled together and poured into molds to harden. In more recent history, bar soap was made by mixing animal fat with lye. Before commerically produced lye was available, it was made at home from ashes. Before the 1850s, it was common to make lye bar soap at home. With the advent of the general store, more people began to purchase pre-made soap to eliminate the dangerous procedure of working with caustic lye.

Lye bar soap is a multi-purpose substance. It can be used for bathing or general household cleaning. Lye bar soap is effective in treating skin problems and rashes. It can even be used to wash laundry by scraping a few flakes from a bar directly into the washing machine.

Lye bar soap is made with sodium hydroxide. This substance produces a hard, bar soap. Traditionally, lye soap was made with lard, but many manufacturers today have substitued oils for animal fat. Aromatic oils and natural dyes are often added to modern bars to make them more appealing to consumers. However, original lye bar soap was free of fragrance or color.

The many benefits of lye bar soap include enhanced whitening when used on laundry and in general household cleaning tasks. It is also effective in treating poison ivy, athlete's foot, head and body lice, dandruff, psoriasis, eczema and acne. Bathing pets with lye soap can control fleas and ticks and reduce itching. Lye bar soap can also help soothe itching and soreness caused by insect bites in humans.

Lye is a chemical and can be dangerous to work with. Always work outside or in a well-ventilated area when making lye bar soap. The lye should never be inhaled or allowed to touch the skin. Wear protective gloves and goggles if possible while working with the substance. Lye has a negative reaction to metal and should only be mixed in glass or plastic containers. Read all manufacturer's instructions before attempting to make your own lye bar soap. Lye is dangerous by itself, but if the soap is made properly there will be no lye left in the finished bars.