When it came to popular products, Mrs Olsen said vitamin C was an "oldie but a goodie". Olive and echinacea products were also popular and Mrs Olsen said people also bought general multivitamins to cover all their bases.
Bethlehem Health and Tea Shop owner Jude Randell said she had noticed an increase in people wanting natural health products over the last few years.
"People are saying such and such didn't work or I can't give cough medicine to my two-year-old. Some people say natural remedies don't work but a few generations ago this is what people used."
Mrs Randell said people came into her shop with conditions and asking for suitable products rather than coming in with specific requests. She said because there were many different ways of treating winter ills it was hard to measure which products had increases in sales.
Health 2000 reported an increase of 18.6 per cent in sales from the year ending 2012 to 2013 in the immune products category. There had also been three times as many sales of vitamin C in the past 30 days than other immune products.
Health 2000 Mount Maunganui owner Cathie Waites said they were in the business of taking preventive health seriously.
"We are happy to help people who want to concentrate on being healthy. As every person's body and lifestyle is different, there is no one-size-fits-all prevention. People can, and do, avoid getting colds or the flu by cultivating a robust immune system and simple practical precautions like hand washing."
Last year, Countdown supermarkets saw a marked increase in sales of products for winter illnesses. A spokesman said there had been an 18 per cent increase in honey, 26 per cent increase in ginger, 32 per cent increase in lemons, 27 per cent increase in hand sanitiser, 9 per cent increase in cough medicines, 9 per cent increase in vitamin C supplements and a 7 per cent increase in tissue sales compared with the previous year.
The spokesman said this indicated people did look at other remedies coming into winter.
Foodstuffs did not respond.