The use of certain herbs could have a positive impact on mood and memory, particularly among older people, new research suggests.

UK researchers have found that drinking chamomile tea has a calming effect, while drinking peppermint tea improves alertness.

Furthermore, smelling the aroma of rosemary appears to enhance the memory of people over the age of 65, while smelling the aroma of lavender appears to impair memory.

The researchers from Northumbria University carried out two studies in this area. In one study, they asked 180 people to drink either peppermint or chamomile tea, while a control group drank hot water. All had their mood and cognition tested before and after drinking.

The study found that peppermint enhanced and aroused mood and cognition, which helped to improve the particiapants' memory and alertness.

Chamomoile, on the other hand, produced a calming and sedative effect, which slowed memory and attention speed.

"Peppermint has a reputation for being psychologically or mentally alerting. It picks you up and makes you feel a little bit brighter, so we endeavoured to test this out by giving people peppermint tea, or chamomile tea, which is a more calming drink and then put them through some computerised tests.

"We found that those people who had drunk the peppermint tea had better long-term memory. They were able to remember more words and pictures that they had seen. In contrast, the people who had the chamomile were slower in responding to tasks," explained Dr Mark Moss of Northumbria University.

In another study, 150 people aged 65 and older were put in rooms that had been scented with lavender or rosemary essential oils, or an unscented control room. They then underwent memory and mood assessment tests.

The researchers found that those in the rosemary scented room had much better prospective memory - this includes the ability to remember to do something at a particular time, such as taking medication.

Their memory test scores were 15% higher than those who had been in the control room and they were also found to be more alert.

Those in the lavender room appeared to be much more calm and content, however, their prospective memory was poorer.

"Rosemary has a reputation about being associated with memory - even Shakespeare said ‘rosemary is for remembrance' - and it's also associated with being invigorating. We have found that people are more alert after being in a room that has rosemary aroma in it. We tested prospective memory - our ability to remember to do something - on people over 65 years of age, to see if we could improve their ability and we found that rosemary could do that.

"This is potentially very important because prospective memory, for example, enables you to remember to take your medication at certain times of the day," Dr Moss said.

He added that the findings suggest that if you are otherwise healthy, ‘there is an opportunity to have an improved memory'.

Details of these findings were presented at the recent annual conference of the British Psychological Society in Nottingham.