People use castor oil, derived from the castor bean plant, to treat conditions including constipation, dry skin and dry hair. However, it also has industrial uses in agriculture and textiles. Castor oil is not considered highly perishable, but you must protect it from certain environmental conditions to prevent rancidity and to optimize efficacy. The Material Safety Data Sheet advises that consumers and commercial handlers store castor oil within specific duration and heat brackets throughout the packaging process and after consumer purchase.

Store castor oil in a pantry or mud room shelf where the temperature averages between 50 degrees and 77 degrees Fahrenheit. Exposure to excessive heat can cause castor oil to decompose.

Protect castor oil from direct sunlight. Exposure to direct sunlight, even in a cool, dry room creates rancidity and causes spoiling. Store castor oil in a closet or cupboard in your home away from moisture and heat.

Limit moisture exposure. Exposing castor oil to moisture expedites the rancidity process and leads to spoiling. For example, a cupboard near your bathroom shower would be a poor choice because of the steam.

Use your castor oil within six months unless otherwise directed. Oil is a volatile substance and will not retain its beneficial properties past the indicated expiration date. Discard any castor oil that appears thick, congealed or clumpy.