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 don't match yours before using penicillin, but penicillin should work well 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 )

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

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

mold should start as 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 put into 500ml of cold tap water 44.000 grams Lactose Monohydrate, 25.0 grams cornstarch, 3.000 grams sodium nitrate, 0.250 grams magnesium sulfate, 0.500 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.