It is time to reconsider the widespread advice that people should always complete an entire course of antibiotics, experts in the BMJ say.
They argue there is not enough evidence to back the idea that stopping pills early encourages antibiotic resistance.
Instead, they suggest, more studies need to be done to see if stopping once feeling better can help cut antibiotic use.
But GPs urge people not to change their behaviour in the face of one study.
Prof Helen Stokes-Lampard, leader of the Royal College of General Practitioners, said an improvement in symptoms did not necessarily mean the infection had been completely eradicated.
"It's important that patients have clear messages, and the mantra to always take the full course of antibiotics is well known - changing this will simply confuse people."
'Short and tailored'
The opinion piece, by a team of researchers from across England, argues that reducing the use of antibiotics is essential to help combat the growing problem of antibiotic resistance.
Prof Martin Llewelyn, from the Brighton and Sussex Medical School, together with colleagues, argues that using antibiotics for longer than necessary can increase the risk of resistance.
He suggests traditional long prescriptions for antibiotics were based on the outdated idea that resistance to an antibiotic could develop when a drug was not taken for a lengthy time and an infection was undertreated.
Instead, he says, there is now growing evidence that short courses of antibiotics - lasting three to five days, for example - work just as well to treat many bugs.
He accepts there are a few exceptions - for example, giving just one type of antibiotic for TB infections - which is known to lead to rapid resistance.
But the team says it is important to move away from blanket prescriptions and, with more research, give antibiotic prescriptions that are tailored to each infection and each person.
The study acknowledges that hospitals are increasingly reviewing the need for antibiotics from day to day and that there is a growing trend towards shorter courses of drugs.
But it questions whether advice such as stopping once feeling better would be beneficial - particularly when patients do not get the opportunity to be reviewed in the hospital every day.
They accept this idea would need more research.
Prof Helen Stokes-Lampard, leader of the Royal College of General Practitioners, says while it is important to take new evidence into account, she "cannot advocate widespread behaviour change on the results of just one study".
She says recommended courses of antibiotics are "not random" but tailored to individual conditions and in many cases courses are quite short.
And she says: "We are concerned about the concept of patients stopping taking their medication mid-way through a course once they 'feel better', because improvement in symptoms does not necessarily mean the infection has been completely eradicated.
Meanwhile, Kieran Hand, spokesman for the Royal Pharmaceutical Society, said: "This opinion article from respected NHS infection experts is a welcome opening of the debate in the UK on the relationship between the length of a course of antibiotics, efficacy and resistance.
"As researchers have pointed out, further research is needed before the 'Finish the course' mantra for antibiotics is changed and any alternative message, such as, 'Stop when you feel better,' can be confidently advocated.
"The ideal future scenario would be that the right length of treatment for a specific infection for patients is identified from clinical trials and the exact quantity prescribed and dispensed."
Public Health England says patients should continue to follow their health professional's advice about using antibiotics.