Gardeners are being advised to wash their hands after coming into contact with compost following a series of rare cases of Legionella over the past five years.
One man has died and five others have become ill after contracting 'Legionella longbeachae', which it is understood to come from compost.
Doctors all over the UK are being urged to be alert for a link with gardening if they see patients with unusual pneumonia.
Symptoms of Legionella longbeachae include headaches, diarrhoea or a dry cough followed by pneumonia.
All those who have contracted the illness so far were very keen gardeners, using different brands of compost.
The strain is well known in Australia and New Zealand, where bags of compost carry warning labels.
But these are the first cases linked to compost to be confirmed in the UK.
"Gardening is a very healthy hobby but like anything in life there's a few risks," said Dr Martin Donaghy, medical director of Health Protection Scotland.
"Over the past five years we've had three confirmed cases of Legionella longbeachae, plus two 'probable' and one 'possible' so we do need to take steps to reduce the risk even further."
Most people recover after treatment with antibiotics and Dr Donaghy said other cases may have gone unreported.
"One of the features of this phenomenon is that we've only seen it in Scotland," he said.
"We're working closely with colleagues in England to find out the reasons for that.”
Specialists are now investigating whether recent changes to compost formulas might be to blame as manufacturers move away from traditional peat-based growing media.
Health Protection Scotland is in discussions with the Scottish government on whether Australian-style warning labels should be recommended to manufacturers.