When we hear the word “drug” it can have negative connotations, but of course there are some drugs that have altered our lives immeasurably for the better, as well.

These 5 drugs changed the world, there’s no doubt about it – but only some of them did more good than harm.

5. Nitroglycerin

When nitroglycerin was invented in 1847 it replaced gunpowder as the world’s most powerful explosive. It was also the first modern drug to successfully treat angina, which is chest pain associated with heart disease.

Unfortunately, factory workers who had been exposed to nitroglycerin began to experience headaches and skin flushing, since the drug is a vasodilator (it opens the blood vessels) – but those reactions allowed researchers to realize it could have purposes other than blowing stuff up.

Nitro has made it possible for millions of people with varying stages of heart disease to live more normal lives, and also paved the way for other blood pressure-lowering drugs, beta-blockers, and statins – all of which have extended the average lifespan in Western countries.

There is a downside even to that, however, as we’re seeing higher rates of death from cancer and other non-communicable disease, but I think that overall, we’re all still better off.

4. Anaesthesia

It was way back in the 1700s when English chemist Joseph Priestly discovered his “phlogisticated nitrous air,” and his fellow scientist Humphry Davy for the idea that it could be used as pain relief in surgery.

At the time, however, it became more of a recreational drug than anything else.

In 1834, French chemist John-Baptiste Dumas discovered chloroform. A few years later, in 1847, Scottish doctor James Young Simpson used it to assist in a difficult birth.

After that it began to be used more often in surgeries, which led to better recovery rates and fewer patients perishing from shock.

All drugs have potential side effects, though, and even modern anaesthetics pose risks of suppressing the nervous system.

3. The Birth Control Pill

In 1951, heiress Katharine McCormick funded research by Gregory Pincus that developed into an effective hormonal contraceptive. He found that progesterone helped stop ovulation, and conducted trials on vulnerable women in Puerto Rico, many of whom did not consent and experienced side affects.

The drug was first released in 1960, approved by the FDA because they viewed the risk of pregnancy to be greater than the risk of the pill’s side effects, like blood clots and strokes.

It took a federal government inquiry into the side effects to get the pill’s hormone levels lowered dramatically, and now we all get a patient information sheet that informs us of associated risks, as well.

The availability of the pill caused major life changes, like people having smaller families, and increased family income as more women were able to maintain lucrative careers even after having children.

2. Penicillin

You’ve probably heard that, in 1928, Scottish physician Alexander Fleming discovered penicillin…on accident.

He went on holiday with some cultures of streptococcus bacteria left out in his laboratory, and upon his return, saw that some airborne penicillin had stopped the bacteria from growing.

It was Australian pathologist Howard Florey who, along with his team, stabilized penicillin and conducted the first human trials – and with help from American financiers, it saved the lives of thousands of men during WWII.

Penicillin has been almost universally good in what it has done, though now we are living in an age where drug-resistant strains of bacteria are cropping up right and left.

1. Diazepam

Librium, first created and marketed in 1955, was the first nervous system depressant available to the public. It, and other similar drugs that followed, were not supposed to be “cures” for things like anxiety, but to assist those who suffered in being better able to engage in psychotherapy.

In 1959, Polish-American chemist Leo Sternbach chemically altered Librium to produce diazepam, which was much more powerful. It was marketed in 1963 as Valium.

Valium and its modern antidepressant counterparts are cheap and easy to get, allowing people to manage stress and anxiety without getting to the root cause with a therapists.

The good thing is that it’s more difficult to overdose on modern drugs, which also have fewer side effects.

Even with the best of intentions, things can go wrong – but it’s always a better place to start from, regardless.