Why does aspirin smell like vinegar

Aspirin is one of the most frequently used OTC (Over the Counter) medications that are used to treat headaches, fever and muscle pain. This drug is also recommended by doctors for heart diseases because it can avoid blood clots. Apart from humans, the medicines are also given to dogs for treating arthritis and general body pain.

There is an element of curiosity as to why Aspirin has a tendency to smell like vinegar. One may notice that the vinegar like smell is usually witnessed in tablets that go bad or which are nearing or has passed expiration date. Aspirin is the common name for acetylsalicylic acid (ASA). It is produced by making use of salicylic acid and making it react with acetic anhydride in the presence of many hydrogen catalysts. When aspirin becomes old, it gradually reacts with the moisture present in the air. The resultant chemical process is aspirin, which is nothing but a byproduct of acetic acid. Incidentally, vinegar too has acetic acid as its most important component.

Aspirin tablets that have high concentrations of acetic acid undergo a reverse process when exposed to wet surrounding or kept past their expiration date. Salicylic acid and acetic acid are released due to the breaking down of ASA. The splitting up process is continuous, producing a smell identifiable with vinegar. The medicine begins to lose its effectiveness as hydrogen atoms disappear and it slips back into its initial salicylic acid-acetic acid combination.

The unhealthy reaction to dampness is the reason why it is mentioned that you should seal medicine bottles and store them in a ‘cool, dry place’. In fact, aspirin bottles used to come with little silicone gel sachets to absorb moisture inside them Some of the recent aspirin tablets come with material that keep wetness away from its ingredients, increasing the longevity of the medicine. To be on the safe side, it is better to ask your doctor if it is fine to take aspirin for body pain Make sure that you check the manufacture and expiration date of the medicine before buying it.