This is a very important question. In my lab I use pure acetone every day to clean and purify my samples. Fortunately, acetone isn’t extremely dangerous, but you should still try to avoid excessive contact with it. Here’s why:

• The estimated LD50 of acetone for a human is about 1.16 g/kg. Which means that for an average 5th grader weighing 35 or so kg, the LD50 would be (35kg) x (1.16g/kg) = 40g of acetone. That’s about 2-3 tablespoons worth. The LD50 is a widely used measure of how poisonous a substance is. It tells you at what dose 50% of the test animals exposed to it die. Substances we would think of as a typical poison have an LD50 of 0.1 to 2 mg/kg – around 1000-fold lower than acetone. Because the LD50 does not tell you at what dose the first or all of the test animals die, it does not tell you that 30 g of acetone are not going to kill you or that 42 g of acetone will kill any person of 35 kg. So don’t drink nail polish! Luckily, you would never want to drink acetone because…

• Acetone burns your eyes nose and throat! Not in the same way fire does, but acetone causes your eyes to hurt and tear up, and makes breathing feel harsh and difficult. That’s your body’s way of telling you “please don’t drink this!” If you breathe too much, you can experience headache, nausea, dizziness, drowsiness, or confusion. You can even become unconscious for extreme doses.

• If you’re worried about nail polish remover though, you’re probably most worried about skin contact. If acetone contacts your skin, it can become red and irritated. Under chronic exposure, you’ll get red, dry, cracked skin. Also, a little acetone will get absorbed into your body, but it’s not enough to be worried about.

• Lastly, acetone is flammable so make sure never to have any fire, sparks, or excessive heat near it! Acetone may not harm your body too much, but fire can! So in general, if you get acetone on you, make sure to rinse that area with warm water. If you get it in your eyes, also rinse them with warm water for a few minutes. Otherwise, your skin will become dry and cracked and your eyes will be irritated for a while. However, acetone won’t give you cancer and it won’t affect your ability to reproduce. So as long as you don’t drink it, you’ll probably be okay in the long run.

Acetone is poisonous, and evaporates quickly so can result in dangerous fumes. It's a pretty simple compound, so the things it does to you are not targeted at any one part of the body. Expose yourself to too much of it in a short time, and you will die. Smaller amounts over longer times will cause various kinds of damage, of which I would guess brain damage to be the worst.

Your great question gives me the opportunity to teach you something that every budding chemist should know: how to look up safety information on chemicals.

Every known chemical that you might find in the lab has a document called a "materials safety data sheet," or MSDS for short. You can go online to find this information. I usually go to the website of a chemical company called Sigma Aldrich (sigmaaldrich.com) and search for the chemical name to find an MSDS, but there are many other places to find these documents on the web as well.

The MSDS gives target organs that are at risk of exposure, and information about other safety issues such as flammability or high reactivity. When I look up acetone, I find that it is a skin and eye irritant, and can affect the liver and kidney if ingested. It´s highly flammable and also an inhalation hazard. It reads specifically that "Repeated exposure may cause skin dryness or cracking."

Keep in mind that the information given in the MSDS is usually for a concentrated form of the chemical. In nail polish remover, the concentration of acetone is lower than in a lab-grade chemical, but it can certainly still cause irritation for some people, and this why acetone-free alternatives are also available for those who are sensitive or who are concerned about the harshness of the acetone product.

Acetone is actually a natural metabolic product in plants and animals. People who have a high fat/low carb diet, exercise strenuously, or have uncontrolled diabetes tend to produce higher than average levels of it.

Usually, acetone is eliminated from the body within a day of exposure. However, too much acetone in the short term can result in nausea, mood swings, and irritation of the eyes and respiratory tract (if the source of exposure is inhalation), and long term effects include dizziness, loss of strength, and malformed gametes (reproductive cells).