How many antibiotics are there?
What the WHO counts, by group, class and new approvals
Matic Broz, PhD8 min
Ask how many antibiotics exist and the answers run from "more than 100" to nearly 300. The best single figure is 268 antibiotics used in humans, the number the World Health Organization sorted into its Access, Watch and Reserve groups in 2025: 93 Access, 145 Watch and 30 Reserve.
That is a count of active substances, not of every brand, dose, veterinary drug or experimental compound. Each of those units gives a different total, which is why a search for one exact number turns up several.
How many antibiotics are there?
The WHO's 2025 AWaRe classification lists 268 antibiotics used in humans.[1] AWaRe stands for Access, Watch and Reserve, three groups that rank antibiotics by their clinical importance and by how strongly their use selects for resistance. Since 2019 the classification has aimed to cover all antibiotics in common clinical use worldwide, which makes it the closest thing to an official global inventory.
| Group | What it means | Antibiotics | On the 2025 Essential Medicines List |
|---|---|---|---|
| Access | Lower resistance potential; first or second choice for many common infections | 93 | 26 |
| Watch | Higher resistance potential; main targets of stewardship and monitoring | 145 | 14 |
| Reserve | Last-resort options for confirmed or suspected multidrug-resistant infections | 30 | 10 |
| All AWaRe groups | 268 | 50 | |
| Not recommended | Fixed-dose combinations of broad-spectrum antibiotics that WHO advises against using | 116 | 0 |
Watch is the largest group because it holds whole classes with high resistance potential, including every quinolone in the file and most cephalosporins. The 2025 WHO Model List of Essential Medicines is a much narrower selection of 50 antibiotics for priority health needs. The same distinction between active substances and products explains why counts of medicines worldwide vary so widely.
We counted the rows of the WHO spreadsheet to see what the 268 consists of. Twelve substances appear twice, once per route, because the route changes how they are used. Oral vancomycin, for example, carries the ATC code of an intestinal anti-infective, while the intravenous form sits with antibacterials for systemic use.[1] Merging those pairs leaves 256 distinct names, 19 of them fixed combinations such as amoxicillin with clavulanic acid.
The list has grown as WHO classified more drugs. It contained 180 antibiotics in 2019 and 257 in 2023, when the split was 87 Access, 141 Watch and 29 Reserve.[2][3] The 2025 update therefore added six Access, four Watch and one Reserve antibiotic.
Why do other counts differ?
Other totals are usually not wrong. They count a different unit. The ATC index, the WHO's drug classification for medicine statistics, has 288 fifth-level codes, the level that names individual substances and combinations, in its group J01, antibacterials for systemic use. When we counted them on October 24, 2026, 58 were combinations, leaving 230 single substances.[4]
That is close to AWaRe's 237 single substances, but the two lists are built for different jobs. ATC gives each pairing of drugs its own combination code. AWaRe also includes 23 entries that ATC files outside J01, such as oral antibiotics that act in the gut, nitroimidazoles coded as antiprotozoals and rifamycins coded as antimycobacterials.[1]
Animal medicine adds another layer. The veterinary version of ATC lists antibacterials such as enrofloxacin, marbofloxacin, tylosin, tulathromycin and tiamulin, none of which appear in the human AWaRe file.[5][1] Products multiply the count further, because one substance such as amoxicillin is sold by many manufacturers as capsules, tablets, suspensions and injections.
The list also lags behind new approvals. Zoliflodacin, approved by the US Food and Drug Administration in December 2025, and cefepime-zidebactam, approved in May 2026, are not in the 2025 file.[6][7] Neither is nitroxoline, a first-line option for cystitis in European guidelines.[8]
How many classes of antibiotics are there?
The WHO's ATC system has 10 main groups for systemic antibacterials. There is no universal class count, because antibiotics can also be grouped by chemical structure, mechanism, spectrum or use.[9][4]
Those 10 groups are tetracyclines, amphenicols, penicillins, other beta-lactams, sulfonamides and trimethoprim, macrolides/lincosamides/streptogramins, aminoglycosides, quinolones, antibacterial combinations, and other antibacterials.[4] The AWaRe file is finer grained and uses 39 class labels, splitting cephalosporins by generation and quinolones from fluoroquinolones.[1]
We grouped those labels into broader families to show where the 268 antibiotics sit. Beta-lactams (penicillins, cephalosporins, carbapenems and related drugs) account for 109 of them, about two in five.
| Family | Access | Watch | Reserve | Total | Examples |
|---|---|---|---|---|---|
| Cephalosporins | 12 | 36 | 5 | 53 | Cefalexin, ceftriaxone, cefiderocol |
| Penicillins | 25 | 10 | 0 | 35 | Amoxicillin, benzylpenicillin, cloxacillin |
| Quinolones and fluoroquinolones | 0 | 32 | 0 | 32 | Ciprofloxacin, levofloxacin |
| Sulfonamides and trimethoprim | 29 | 0 | 1 | 30 | Sulfamethoxazole/trimethoprim, iclaprim |
| Aminoglycosides | 3 | 17 | 1 | 21 | Gentamicin, amikacin, plazomicin |
| Macrolides, lincosamides and streptogramins | 1 | 18 | 1 | 20 | Azithromycin, clindamycin |
| Tetracyclines | 2 | 10 | 4 | 16 | Doxycycline, tigecycline |
| Other beta-lactams | 5 | 3 | 3 | 11 | Amoxicillin/clavulanic acid, aztreonam |
| Nitroimidazoles | 11 | 0 | 0 | 11 | Metronidazole, tinidazole |
| Carbapenems and penems | 0 | 7 | 3 | 10 | Meropenem, faropenem |
| Glycopeptides and lipopeptides | 0 | 3 | 4 | 7 | Vancomycin, daptomycin |
| Other classes | 5 | 9 | 8 | 22 | Rifampicin, colistin, linezolid, nitrofurantoin |
| All classes | 93 | 145 | 30 | 268 |
The short lists of six or seven "types of antibiotics" in patient leaflets name the largest of these families and leave out the small ones. Popular lists also often count cephalosporins, carbapenems and monobactams as separate classes, while the ATC system places them together under "other beta-lactam antibacterials". Differences in splitting and grouping explain why credible class counts do not match.
The counting script, class counts (CSV) and ATC counting script reproduce every count we derived in this article from the WHO spreadsheet, file B09489-eng.xlsx, and from the ATC index, both retrieved on October 24, 2026.
How many antibiotics are there for UTIs?
Current European guidelines name four first-line antibiotic options for cystitis in women: fosfomycin, pivmecillinam, nitrofurantoin and nitroxoline. There is no fixed count for every type of UTI.[8]
The same guideline lists cephalosporins, trimethoprim and trimethoprim-sulfamethoxazole as alternatives under specific conditions. Kidney infections, complicated UTIs, pregnancy, allergies, kidney function and resistant bacteria require different choices.
The options keep changing. The FDA approved pivmecillinam for uncomplicated UTIs in adult women in 2024 and gepotidacin for uncomplicated UTIs in female patients aged 12 years and older in 2025.[10][11]
In 2026 it added two drugs for complicated UTIs, including kidney infections: cefepime-zidebactam in May and tebipenem pivoxil in June, the latter for adults with few or no other oral options.[7] A urine culture and local resistance data narrow the choice for an individual infection.
How many new antibiotics have been approved?
Seventeen new antibacterial agents against WHO priority pathogens received marketing authorization between July 2017 and February 15, 2025, the cut-off of WHO's latest pipeline analysis. Only two represented a new chemical class.[12][13]
Since that cut-off, four antibacterials have appeared on the FDA's list of novel drug approvals, two in each year. Gepotidacin is already in the 2025 AWaRe file, as a Watch antibiotic and the only member of its class.[6][7][1]
| Antibiotic | Brand | Approved | Approved use |
|---|---|---|---|
| Gepotidacin | Blujepa | March 25, 2025 | Uncomplicated urinary tract infections |
| Zoliflodacin | Nuzolvence | December 12, 2025 | Uncomplicated urogenital gonorrhea |
| Cefepime and zidebactam | Zaynich | May 29, 2026 | Complicated urinary tract infections, including pyelonephritis |
| Tebipenem pivoxil | Utebzi | June 17, 2026 | Complicated urinary tract infections in adults with limited oral options |
Antibacterials made up 2 of the FDA's 46 novel approvals in 2025 and 2 of the 47 it had approved in 2026 by October 20.[6][7] The pipeline behind them is thin. In 2025, WHO counted 90 antibacterial agents in clinical development, down from 97 in 2023. Fifty were traditional antibiotics and 40 were non-traditional approaches such as bacteriophages, antibodies and microbiome-modulating agents.[12]
Only 15 of the 90 met at least one of WHO's innovation criteria, and only five were active against at least one critical-priority bacterium. Further back, WHO counted 232 preclinical programmes across 148 groups, and about 90% of the companies involved had fewer than 50 employees.[12] That work spans drug discovery, molecular docking, laboratory studies and clinical trials.
None of these candidates changes the 268 until WHO classifies it, and even approved drugs such as zoliflodacin wait for the next update. The WHO figure is best read as a count of the antibiotics in use when the 2025 classification was made: large, dominated by beta-lactams, and replenished by only a few new agents a year.
ProteinIQ. "How many antibiotics are there?" Updated October 24, 2026. Accessed [your access date]. https://proteiniq.io/guides/how-many-antibiotics-are-there
