Is Silica Gel Toxic?

What is silica gel and what is it used for?

Silica gel is a form of silicon dioxide. Its chemical make-up and high surface area allow it to easily absorb water, making it a useful drying agent (i.e., desiccant). Silica gel packets are used in pill bottles to decrease moisture, which helps preserve the pills. It is usually available as beads, granules, or crystals in a permeable bag or, less often, in a cylindrical canister. The beads or granules are clear or white, unless coated with an indicator to tell you whether the silica gel has already absorbed moisture and should be replaced. 

The instruction, “Do Not Eat,” is printed on the bag or canister. Diagnostic test strips, drug test kits, and devices used for inhaling medications may contain silica gel. The packets are also found in shoes, clothing, electronic equipment, cameras, pocketbooks, wallets, and other non-medical items. Food grade silica gel is safe for food storage.

Is silica gel harmful to your skin?

Silica gel is not very harmful to your skin, but it is possible for redness and irritation to occur if silica gel comes into contact with your skin. 

Are desiccant silica gel packets toxic?

Desiccant silica gel packets are considered non-toxic. 

Why does silica gel change color?

Some silica gels are coated with orange/yellow or blue indicators. These indicator chemicals change color to let you know when silica gel has absorbed moisture and needs to be replaced. Silica gels coated with indicators are not used to protect medicines or food from moisture. Rather, they are used to keep electronic equipment dry to avoid corrosion.

Orange/yellow silica gel desiccants usually contain methyl violet and turn green when moist. Their toxicity is low. Blue silica gel desiccants are coated with an indicator called cobalt chloride. When blue silica gel becomes moist, the cobalt chloride changes color from blue to pink, which indicates that the silica gel should be replaced. While cobalt chloride is toxic, the concentration is low (i.e., 1% or less) and therefore even cobalt-containing silica gel is usually safe if accidentally ingested. If large amounts (e.g., multiple packets or a large pack) of blue silica gel are swallowed, check webPOISONCONTROL online for a case-specific answer, or call Poison Control at 1-800-222-1222 to make sure the amount is still safe. 

Is silica gel poisonous? What happens if you eat silica gel?

Standard white or clear silica gel is not poisonous and swallowing it is considered a non-toxic ingestion. Likewise, silica gel with an orange/yellow indicator coating is also minimally toxic. If silica gel is accidentally swallowed, it will not cause adverse effects in most people. However, in young children, the silica gel packet can possibly present a choking hazard. Blockage of the esophagus or stomach by the packet or cannister has also occurred in adults. See above for more about blue-colored indicating silica gel, which is slightly more toxic, but safe if swallowed in small quantities.

If silica gel gets in the eyes, it may cause redness and irritation. Rinse your eyes with water. If silica gel granules or crystals are inhaled, lung irritation, coughing, or shortness of breath are possible. Breathing fresh air is recommended.  

What should I do if I ate silica gel?

If you ate silica gel, rinse out your mouth. If someone swallows silica gel, gets silica gel in the eyes, or if you have a question about using silica gel safely, help from experts is available through the webPOISONCONTROL online tool and by phone at 1-800-222-1222. Poison Control’s expert guidance is always free, confidential, and available 24 hours a day.

Wendy Klein-Schwartz, Pharm.D., MPH
Clinical Toxicologist

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