There are three basic classes of mineral oils:
Due to its low price and ubiquitous supply, mineral oil has been pressed into service in a wide variety of capacities. Most of these exploit its properties as a low-toxicity, non-reactive general purpose lubricant and coolant.
Mineral paraffinic oil is sometimes taken orally as a laxative. It lubricates intestinal mucous membranes and limits the amount of water removed from the feces, leaving them soft and easy to pass. Mineral oil is effective within as little as six hours. While it has been reported that mineral oil may be absorbed when emulsified, most information shows that it passes harmlessly through the gastrointestinal system. It is often prescribed, over the counter, to young children who become "stool holders." Such children have had a painful bowel movement that leaves them in fear of having another. A vicious cycle then develops when the child holds the stool in, where it becomes even dryer and harder. The child's pediatrician will recommend the proper dosage, along with vitamins (a few of which are not as well absorbed during mineral oil treatment). It is colorless, odorless and flavorless, but its slight viscosity is better tolerated cold, direct from the refrigerator. It is administered in a child's medicine dropper like any other liquid, and can be discontinued as soon as the child loses his or her fear of having a painful bowel movement. It works equally for adults, when adding fiber to the diet has not been as effective as desired.
Use with caution if a person has a bad cough. If used at all, mineral oil should never be given internally to young children, pets, or anyone with a cough, hiatus hernia, or nocturnal reflux, and should be swallowed with care. Due to its low density, it is easily aspirated into the lungs, where it cannot be removed by the body and can cause serious complications such as lipoid pneumonia. While popular as a folk remedy, there are many safer alternatives available. In children, if aspirated, the oil can work to prevent normal breathing, resulting in death of brain cells and permanent paralysis.
Every treatment has a worst case scenario, but most children have no trouble swallowing oily substances.
Mineral oil with added fragrance is marketed as baby oil in the US, UK and Canada. While baby oil is primarily marketed as a generic skin ointment, other applications exist in common use. It is best to use this oil on infant "diaper rashes" to ease the inflammation. Mineral or baby oil is often used in small quantities (2–3 drops daily) to clean ears. Over a couple of weeks, the mineral oil softens dried or hardened earwax so that a gentle flush of water can remove it. In the case of a damaged or perforated eardrum, however, mineral oil should not be used, as oil in the middle ear can lead to ear infections. It is also a recommended way of removing an insect from the ear of a human. A few drops drowns the invader, which can then be easily removed.
Mineral oil is used as suspending and levigating agent in sulphur-based ointments.
Certain mineral oils are used in livestock vaccines, as an adjuvant to stimulate a cell-mediated immune response to the vaccinating agent. In the poultry industry, plain mineral oil can also be swabbed onto the feet of chickens infected with scaly mites on the shank, toes, and webs. Mineral oil suffocates these tiny parasites. In beekeeping, food grade mineral oil saturated paper napkins placed in hives are used as a treatment for tracheal and other mites.
Mineral oil is a commonly-found ingredient in baby lotions, cold creams, ointments and low-grade cosmetics as an alternative to more expensive oils. According to some sources, use of mineral oil cosmetics commonly leads to acne. It can be used on eyelashes to prevent brittleness and breaking and, in cold cream, is also used to remove creme makeup and temporary tattoos.
Mineral oil is used in a variety of industrial/mechanical capacities as a non-conductive lubricant. Refined mineral oil is used as transformer oil. Electric space heaters sometimes use it as a heat-transfer oil, and it can be used generically as a coolant in electric components as it does not conduct electricity.
Because it does not absorb water from the air, mineral oil can be used as an automotive, aviation, and bicycle brake fluid.
See also lubricant
Since it does not absorb atmospheric moisture, mineral oil is useful as a protective coating or bath for water-sensitive materials. Alkali metals like lithium are often submerged in mineral oil for storage or transportation.
Mineral oil is also often used as a coating on metal tools and weapons, knives in particular, as a way to inhibit oxidation. Nihonto, for example, are traditionally coated in Choji oil which consists of 99% mineral oil and 1% oil of cloves. The use of oil of cloves is sometimes explained as a means of differentiating sword oil from cooking oil to prevent accidental ingestion, but may also be purely aesthetic.
Mineral oil's ability to prevent water absorption, combined with its lack of flavor and odor, make it a popular preservative for wooden cutting boards and utensils. Rubbing a small amount of mineral oil into a wooden cutting board periodically will prevent absorption of food odors and ease cleaning, as well as maintaining the integrity of the wood, which is otherwise subjected to repeated wetting and drying in the course of use.
It is occasionally used in the food industry (particularly for candy). In this application, it is typically used for the glossy effect it produces, and to prevent the candy pieces from adhering to each other. It has been discouraged for use in children's foods, though it is still found in many candies, including the popular movie theater treat Swedish Fish.
It can be used as a release agent for baking pans and trays, but food oils like vegetable oil are a more popular choice.
Mineral oil can be used to clean heavier oil stains by diluting and liquefying the other oils, rendering the oils more accessible to detergents. Likewise, it can be employed to "de-gum," to remove adhesive residue left by price tags or adhesive tape. It can be used as a cleaner and solvent for inks in fine art printmaking as well as in oil painting, though turpentine is more often used.
Mineral oil is also used in some guitar string cleaners, since it can help mobilize dirt and oil without contributing to the oxidization of the metal strings.
Mineral oil can leave a residue, which is undesirable in some applications.
Mineral oil is the main fuel used by professional firespinners and firebreathers. It is chosen for its high flashpoint and low burning temperature. As a firebreathing fuel it is ideal because it will not tend to burn as a liquid, due to the high flashpoint, thus preventing blowback.
Mineral oil's ubiquity has led to its use in some niche applications as well.
The broad range of applications for mineral oil has resulted in an equally expansive list of application-specific names and trade brands. Other names for mineral oil include: