Penicillin

Disclaimer: I am not a professional and if you quote this stuff you may be wrong if my sources are wrong

Penicillin is an antibiotic made by the mold species "penicillium chrysogenum"

penicillin was first discovered in 1928 by Alexander Fleming

Due to antibiotic resistance some bacteria have developed resistance to penicillin, as of writing the bacteria that have resistance to penicillin are Staphylococcus aureus, Streptococcus pneumoniae, Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterococcus faecium, Campylobacter jejuni, Mycobacterium tuberculosis. So in the case that you are sick check to make sure the diseases listed dosent match yours before useing penicillin, but penicillin should work good against bacterial infections with gram positive and negative cocci, gram positive rods, and most anaerobes

Making penicillin ( disclaimer you may grow penicillium chrysogenum but you have a high chance of also growing mold that could kill you so if you want to try this don't use it on youself!!!unless you are supervised by a professional is supervising you and they have a phd in this field )

First sterilize a container and get rotting material (rotting bread, old cantalope, etc) , a flask would do nicely but a glass bottle could work too.

to sterilize a glass bottle / flask heat it to 315 Fahrenheit(or 158 degrees Celsius, or a yellow flame if you are using fire) for about an hour

mold should start as a grey but then should develop into a blue/greenish color, once the mold starts cut up the rotting material of choice into pieces that can fit into the sterilized container

Then incubate the container at around 70 degrees Fahrenheit or around 22 degrees Celsius for around a week

then to extract the penicillin you must "Into 500ml of cold tap water put 44.0 grams Lactose Monohydrate, 25.0 grams cornstarch, 3.0 grams sodium nitrate, 0.25 grams magnesium sulfate, 0.50 grams potassium phosphate mono, 2.75 grams glucose monohydrate, 0.044 grams zinc sulfate, 0.044 grams manganese sulfate. Then add enough cold tap water to make one liter. Use hydrochloric acid to adjust the pH to between 5.0 and 5.5." But I don't think anyone reading this (including myself) don't know how to obtain some of those chemicals