I want to check the adverse events of aspirin drugs in the open fda data within the specified date I have tried many times and it keeps getting an error display Where did I go wrong ? How can I query correctly? I try to:

https://api.fda.gov/drug/event.json?search=patient.drug.openfda.pharm_class_epc:"aspirin+Antipyretic and analgesic+drug"&limit=1


2 Answers 2


I think the URL you are using has quotation marks (") which are enforcing an exact match.

Please try this URL



Here is the query that searches across the entire dataset: https://api.fda.gov/drug/event.json?search=patient.drug.openfda.substance_name.exact:%22ASPIRIN%22

You can narrow down further by specifying a date range such as: https://api.fda.gov/drug/event.json?search=patient.drug.openfda.substance_name.exact:%22ASPIRIN%22+AND+receivedate:[2020-01-01+TO+2020-01-31]

  • what is the difference between using brand_name vs substance_name: ASPIRIN? In JSON, I don't find any difference. Feb 10, 2022 at 15:11

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