Why do we allow pharmaceutical companies to patent their drugs?

Because their research goes to waste. The pharmaceutical industry is a business, after all. The funds they receive come from private donors. If the company doesn't patent a drug, then it's not profitable because any company can use their research or 'secret recipe' and make a knock-off of that drug, increasing competition and reducing profitability. Luckily, however, all drugs have an expiry date on their patents. In other words, without patents, no one would be inclined to research and mass produce medicine to benefit human health.

thank you!!!