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GSK is a big drug company that invents and sells medicines and vaccines to treat and prevent diseases.
GSK is one of the world's largest drugmakers, a British company that discovers, tests, and sells medicines and vaccines. It sells two main kinds of products: prescription drugs that treat diseases like asthma, HIV, and cancer, and vaccines that protect people from things like shingles and flu. Its customers are mostly doctors, hospitals, and governments — really, anyone who decides which medicine a patient gets. People don't buy GSK pills the way they buy toothpaste; they get them because a doctor prescribed them or a health system ordered them.
The business works like this: GSK spends huge sums on scientists and lab work to find a molecule or a vaccine that works. Then it runs years of clinical trials to prove it's safe and effective, then gets regulators to approve it, then sells it — often under patent protection that gives it years of exclusive pricing before cheaper copies arrive. That's why drug companies are obsessed with patents: the patent is the money machine. A single successful medicine can earn billions, while a failed trial can burn hundreds of millions with nothing to show for it. GSK is particularly strong in vaccines, an area where the science is hard, the factories are expensive, and rivals find it tough to copy — a real moat. GSK hasn't always been a pure drug company. For years it also sold consumer staples — Sensodyne toothpaste, Advil painkillers, Voltaren gel — through a division called consumer healthcare. In 2022 it spun that business off into a separate company called Haleon, so GSK could focus entirely on medicines and vaccines. That's a classic move: separate the steady, slow-growing toothpaste business from the risky, high-reward drug business so each can be valued on its own terms. GSK also fended off a big takeover approach from Unilever in 2022 for that consumer unit, preferring to spin it out instead.
The messy part: GSK has been haunted by litigation over Zantac, an old heartburn drug. Concerns about a breakdown chemical led to thousands of lawsuits, and while GSK has settled many, the overhang has dented its shares. More recently, GSK has bet heavily on its shingles vaccine Shingrix and on an HIV portfolio it shares with Pfizer, and it's been investing in areas like oncology and respiratory disease. Rivals include Pfizer, Merck, AstraZeneca, and Sanofi — all chasing the same patents and the same doctors. GSK's challenge is familiar to every drugmaker: pipelines age, patents expire, and you must keep finding the next big medicine before the old ones run out of protection.
Saved answer · last researched 23 Oct 2026