Pharmacists are being warned not to supply homeopathic or "alternative" medicines if they lack medical evidence showing they are effective treatments.

Australia's peak body representing pharmacists is urging members to stop selling homeopathic products and "alternative" medicines to patients if there isn't any medical evidence to show they can treat or prevent illnesses.

The Pharmaceutical Society of Australia made the call in a set of six new guidelines it released as part of a wider campaign by the independent group NPS Medicine Wise to encourage clinicians and patients to discuss tests, treatments and procedures that don't provide any benefits.

The PSA says if patients choose to buy a homeopathic treatment that isn't backed up by evidence of its effectiveness, health professionals should discuss the lack of benefit with them as they could be putting their health at risk.

The guidelines also urge pharmacists not to recommend complementary, or "alternative" medicines such as vitamins, herbal and aromatherapy products unless there's evidence of their benefits.

"In regards to homeopathic products there is no reliable evidence of efficacy," PSA national president Dr Chris Freeman said.

"All health professionals should take the time to discuss with health consumers, who are taking or considering taking these products, the lack of efficacy and the risks in rejecting or delaying other treatments known to be safe and effective."

The PSA's guidelines also urge pharmacists not to dispense a repeat prescription for antibiotics without first checking it is appropriate.

The guidelines say that while repeat antibiotics can form part of treatment plans for some chronic conditions, inappropriate use of the drugs can result in infections progressing and contribute to antibiotic resistance.

"In other cases patients commonly request dispensing of repeat antibiotic prescriptions without consultation with their treating doctor, and sometimes well after the original prescription was written," the guidelines say.

"If a repeat prescription for an antibiotic is requested to be dispensed, consider the clinical appropriateness of the request."

The other recommendations cover sedatives including benzodiazepines, and precautions to follow for people taking five or more medications.