Why does medicine taste bad?

(Web Desk) - For something curative and healing, most medicines have a surprisingly noxious taste. From bitter-tasting syrups to the persistent metallic aftertaste of certain tablets, why do many of our best treatments taste so bad — and how much does this actually matter?

The majority of modern drugs were developed from or inspired by compounds found in nature, particularly in static species such as plants and marine invertebrates like sponges and corals.

"They cannot move. They cannot escape. So the only tool that they have to defend themselves from predators is to produce chemicals and they are usually compounds that are, to some extent, toxic for humans or other animals,' Orazio Taglialatela Scafati, a pharmaceutical biologist at the University of Naples Federico II in Italy, told Live Science.

Over millions of years, these plants and animals evolved to produce compounds which interact with different receptors in their predator species, whether it's heart-stopping cardiac glycosides in foxgloves, hallucinogenic alkaloids in belladonna, or toxic taxane compounds in yew berries.

In response, humans (and many other animals, too) evolved taste receptors to detect these harmful compounds, with the bitter taste serving as a clear signal to avoid those potential foods. The bitter taste is therefore a warning sign that a particular chemical is likely to change the normal chemistry of the body.

Fast forward a few tens of thousands of years and modern science began helping us understand specifically how these compounds interact with our bodies, enabling us to harness their potent physiological effects in safe and effective medicines. Relatively few medications use these compounds exactly as they are produced by the organism, rare examples being antibiotics such as penicillin and painkillers like morphine.

The majority instead draw inspiration from the chemical structure of the natural products, mimicking their biological activity with a few targeted improvements.