Magical Antibiotics

Any time a character develops an illness of any variety whatsoever, the medical provider will immediately insist upon throwing all manner of high-powered antibiotics at the patient in order to treat the "infection." This is a colossal fail, as there are thousands of species and dozens of classes of infectious organisms - bacteria, viruses, protozoans, fungi, yeasts, helminths [worms], parasites not otherwise specified, and so on. Of those, only bacteria are susceptible to antibiotics, and then only if that particular bacterial strain is sensitive to the prescribed antibiotic (notable examples include MRSA, methicillin-resistant Staphylococcus aureus, and VRE, vancomycin-resistant Enterococcus).

There are antifungal, antiviral and antiparasitic drugs, but these are hardly ever mentioned in fiction (except in medical fiction where they're likely to be a plot point). See also Magic Antidote.

Film

 * Antiviral rather than antibiotic, but in Outbreak, Robbie contracts the Motaba virus and is on the brink of death before they administer the virus' antiserum. She is almost completely recovered after only a day. In reality, this is far too soon to recover from a hemorrhagic fever, which causes massive internal bleeding and organ failure.

Live Action TV

 * Played with on House: first prescribe the most widely useful antibiotics, then find out what they actually have before the patient's kidneys shut down because of the antibiotics.
 * This is true in real life.
 * Especially so if the patient has been brought to the ER with suspected bacterial meningitis. (Viral meningitis can be so mild you might just think you have a nasty headache.) If the doctors do not start broad-spectrum antibiotic therapy immediately, they may well lose the patient quite swiftly - they do this to keep the patient alive while they take blood and CSF (yay for needles in your spine) to find out what the bacteria actually is so they can aim their antibiotic to the particular bug. This mass-antibiotic is known as Empiric Therapy.
 * Meningitis itself - nasty disease that swells the lining of the brain, alters consciousness and in the case of some bacterial forms, comes hand in hand with septicaemia. Every time this troper's seen it on TV they have only started panicking once the rash appears, that red rash that won't disappear under a glass!! Three things: 1. the purpuric rash is generally appears only in bacterial meningitis and is a sign of severe internal bleeding, meaning that 2. if you haven't started treatment by the time the rash appears you might be way too late, and 3. while rather specific as a symptom, meningitis is not the only disease that has this rash. Seriously, don't look for the rash; the four major symptoms to watch for are fever, a stiff neck, dislike of bright lights and a severe headache. On that note, be doubly sure about the fever (since otherwise your friend could just have a hangover).
 * This trope also applies to cancer treatments. While in reality there are dozens of families of antineoplastic drugs, any of which is only effective and used on a handful of specific cancers, House's team is fond of using one-size-fits-all chemotherapy.
 * Well, yes and no. In the rare cases where the team actually treats for cancer, the precise medicines used are very often not mentioned. More recently, House has been in the habit of just turning cancer patients over to Wilson (an oncologist) if cancer is the final diagnosis, or having Wilson come in on the case and make the possible prescriptions if it isn't.
 * House is one of those rare examples in fiction that acknowledges the existence of separate treatments for fungal and parasitic infections.
 * Averted in a Jon Pertwee Doctor Who story which has a major subplot about a deadly plague being released by the story's antagonists. The Doctor and Liz Shaw eventually find a cure by literally going through every single available antibiotic drug to see if it works in lab conditions. In the meantime the best they can do is use high doses of broad-spectrum antibiotics which are just effective enough to delay the plague's symptoms, and a character notes that this policy is causing severe side effects.
 * Averted in Combat Hospital. In the second episode, the antibiotics the hospital staff keep doling out have no effect on a local strain of bacteria.

Video Games

 * Dr. Mario. Thankfully, he has the cure.

Real Life

 * Sadly prevalent in real life medicine, as providers frequently don't want to wait to culture an organism before attempting to treat it. A major cause of the explosion in the rates and severity of multidrug-resistant bacterial infections.
 * Cultures take a couple of days, so the doctors use empiric treatment for the more common bacteria, while they wait for the results of the culture. For any disease causing a high fever, waiting for the cultures before treating it would leave the doctor knowing exactly what drug to use on a patient who'd been dead for days. There are PCR antigen analyses available for some pathogens that are accurate within hours, but they generally don't show up in day-to-day practice due to their overwhelming expense and lack of insurance reimbursement. A few notable exceptions to this rule include influenza, respiratory syncytial virus, Clostridium difficile and Streptococcus - all exceptionally common diseases for which the test achieves an economy of scale.
 * Antibiotics being given when the doctor knows it's the common cold. Sure, some say it's to protect against "secondary infections", but really it's done so they can give some sort of prescription to a patient - or more commonly, to a pediatric patient's parent - insisting on one.
 * Some pediatricians and family practice providers are starting to avert this by giving "supportive therapy" prescriptions for acetaminophen PRN, rest and oral fluids to patients with known viral diseases such as common colds and flu, and "watchful waiting" prescriptions for likely viral problems like ear infections and sinusitis - the patient goes home with a script to be filled only if the symptoms worsen within a three-day period. Patients, by and large, are not impressed by this practice and will actually doctor-shop, going to multiple providers over several days until they find someone who'll write them that magic script.
 * Dr. Drew Pinsky noted on an episode of Loveline that azithromycin (known best under the brand name Zithromax) is frequently given as a catch-all treatment, and estimated that it was the appropriate treatment for maybe 10% of those cases in which he's seen it prescribed.
 * The 1918 influenza pandemic. At least in the US, doctors tended to jab untested or marginally tested "vaccines" into as many arms as they could manage in the hopes that this time, they had it right. (Given that medical science of the early 1900s assumed that influenza was a bacterial disease, any cures would have been accidental.)
 * Of course antibacterial treatments might protect from secondary pneumonia and similar killers piggybacking on the 'flu ... but given that they didn't even have sulfa drugs operational in 1918, you really would have been whistling in the dark injecting anything.
 * In the case of the 1918 pandemic, this would've probably been counterproductive, since what made that flu strain so lethal was probably that it induced cytokine storms in sufferers which turned their own immune systems against them. Having a weakened immune system during the pandemic could actually have been a benefit because the cytokine storms would've been less severe. Of course it's important to note that the doctors dealing with the 1918 pandemic couldn't possibly be aware of this.
 * At least they were still 10 years away from discovering antibiotics. If they had those for the Spanish flu, MRSA would've become a problem by 1920.
 * Lest history judge them too harshly, when 20-50 million people are dying out of a population of about 1 billion, anything which current theory suggests might help will be tried. Given the number of people killed, the number afflicted was staggering and pretty much uncountable.