A5376 Sigma

Acetylsalicylic acid


Synonym: 2-Acetoxybenzoic acid, O-Acetylsalicylic acid, ASA, Aspirin



Related Categories A to C, Application Index, Arachidonic Acid Cascade, Biochemicals and Reagents, Cancer Research,
assay   ≥99.0%
form   powder
color   white
pKa (25 °C)   3.5
mp   134-136 °C(lit.)
solubility   H2O: 10 mg/mL at 37 °C(lit.)
  H2O: 3 mg/mL at 25 °C(lit.)
  ethanol: 50 mg/mL
  aqueous base: decomposes
absorption   ε1mM/230 nm, aqueous acid 466
  ε1mM/231 nm, aqueous base 409
  ε1mM/278 nm, aqueous acid 68
  ε1mM/298 nm, aqueous base 190
Gene Information   human ... ITGA2B(3674), ITGB3(3690), PTGS1(5742), PTGS2(5743)


Frequently Asked Questions

Frequently Asked Questions are available for this Product.

Biochem/physiol Actions

Blocks the production of prostaglandins by inhibiting cyclooxygenase (prostaglandin H synthase), with greater selectivity toward the COX-1 isoform. The antithrombotic effect is due to the inhibition of COX-1 in platelets that blocks thromboxane production and platelet aggregation. Chemopreventive against colorectal and other solid tumors.


1 kg in poly bottle

100, 250, 500 g in poly bottle

Price and Availability

LC-MS Grade Solvents and Reagents

All labs need water

Biomedical Applications
Safety & Documentation

Safety Information

GHS07  GHS07
Signal word 
Hazard statements 
Precautionary statements 
Personal Protective Equipment 
NONH for all modes of transport
WGK Germany 
Flash Point(F) 
482 °F
Flash Point(C) 
250 °C

Frequently Asked Questions

Which document(s) contains shelf-life or expiration date information for a given product?
If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis. These documents are located on the product detail page under Useful Links & Tools. Click on the following link to search for a Certificate of Analysis. Please click the following link to see the details on our Product Dating Information.
How do I get lot-specific information or a Certificate of Analysis?
A Certificate of Analysis is available by lot number and can be obtained through our Advanced Search Option:
How do I find price and availability?
There are several ways to find pricing and availability for our products.  Once you log onto our website, you will find the price and availability displayed on the product detail page. You can contact any of our Customer Sales and Service offices to receive a quote.  USA customers:  1-800-325-3010 or view local office numbers. 
What is the Department of Transportation shipping information for this product?
Transportation information can be found in Section 14 of the product's (M)SDS. To access the shipping information for this material, use the link on the product detail page for the product, or search here. 
My question is not addressed here, how can I contact Technical Service for assistance?
Use the option to the right to "Ask a Question" by email of a Technical Service Scientist.
How does aspirin act as an anticlotting agent?
There may be multiple modes of action which result in the anticlotting properties of aspirin. Some studies have indicated a decrease in thrombin levels and others reduced clotting properties of fibrinogen.
Is Product A5376, Acetylsalicylic acid, offered by Sigma-Aldrich different from that found in aspirin tablets from the drug store?
The active ingredient acetylsalicylic acid offered by Sigma-Aldrich is the same chemical as found in aspirin tablets. However, chemicals for pharmaceutical use are manufactured, tested, and packaged under the regulation of the FDA, but chemicals sold for research use do not have the same regulatory oversight.
How should solutions of Product A5376, Acetylsalicylic acid, be prepared and stored?
Acetylsalicylic acid is slightly soluble in water, with a limit of solubility reported as approximately 3 mg/ml at 25 Deg C.  It is also soluble in ethanol at 50 mg/ml and will dissolve in solutions of alkali hydroxides and carbonates with decomposition.  Aqueous solutions of acetylsalicylic acid are most stable at pH 2 - 3, but to assure full activity, fresh solutions are recommended.
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Peer-Reviewed Papers


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