Scientists are human just like you and I, and with our humanity comes susceptibility to accidents. Some accidents such as getting drunk and texting your ex will bring nothing but regret and a headache. Other mistakes can bring unexpected yet positive outcomes. Believe it or not, many of the medical treatments and procedures we use today were the result of a scientific blunder. Here are four examples of medicines and treatments used every day that may not have come around if it weren't for human error.

Penicillin

Penicillin, according to ABC News, is one of the top 10 health advancements to have changed the world, and ironically enough, it was discovered accidentally. In 1928, Scottish bacteriologist Sir Alexander Fleming left a petri dish filled with the Staphylococcus aureus bacterium uncovered for several days. Upon returning, Fleming found the dish to be contaminated with mold. He was about to throw away the culture when he noticed the mold appeared to be dissolving the bacteria away.

Upon further testing, Fleming discovered that it was actually something in the mold that stopped the growth of bacteria. However, it wasn’t until 1935 that two researchers from Oxford University would separate and purify the penicillin from the mold. This opened to the door to a variety of antibiotics and has saved millions of lives from dangerous infections.

Viagra

Although Viagra may not have saved any lives and isn’t likely to be recognized as one of the top 10 health advancements, the BBC reports that the little blue pill is the fastest selling drug of all time. However, it is not used as it was initially intended to. Before Viagra became what it is today, it was an ordinary new treatment for angina, a heart condition that constricts the vessels supplying the heart with blood. Its trials proved to be disappointing at helping prevent anginas, but volunteers did report one particularly surprisingly side effect: an increased number of erections.

“What was amazing about this study was that we saw a restoration of the erectile response. Now we were on to something which could only be described as special,” Chris Wayman, a senior scientist at Pfizer explained, the BBC reported. Now Viagra is one of the most prescribed drugs in the world and has proved that the failed angina treatment was anything but a mistake.

Pap Smear

When the Pap Smear was introduced in the 1940s, cervical cancer was the number one killer of women. Today, it is a standard cancer screening test for all women and has greatly reduced the death rate from cervical cancer throughout the world. When Dr. George Papanicolaou, nicknamed Dr. Pap, administered his first smear tests, he had no idea of the implications that would follow. According to PBS, Dr. Pap began his studies by observing the vaginal smears of animals during their sex cycle.

Upon shifting his focus to human females, the doctor just so happened to receive a fluid sample of a woman suffering from uterine cancer. Papanicolaou was amazed to find that the abnormal cancer cells could be easily seen under a microscope. “The first observation of cancer cells in the smart of the uterine cervix gave me one of the greatest thrills I ever experienced during my scientific career,” the doctor wrote of his discovery, PBS reported.

The Pacemaker

Wilson Greatbatch, the creator of the pacemaker, actually set out to create an internal heart rhythm recording device for the Chronic Disease Research Institute. According to The New York Times, the inventor accidently installed the wrong part in his prototype. The resistor Greatbatch fitted his device with caused its circuit to produce emitted intermittent electrical pulse. Subsequently, instead of recording heartbeats as Greatbatch had planned, the device started to send out pulses. Greatbatch immediately associated the pulses with a human heartbeat, and thus the pacemaker was born. The pacemaker is used today to monitor and record the heart’s electrical activity and rhythm, and has saved countless lives since its invention.