Canadian resident Kim Davis said she was surprised when she was sorting through her mail last week and saw in bold letters through an envelope window, "RE: Cannabis for Medical Purposes."

The unopened letter was addressed to her husband, a veteran, who in September started taking edible cannabis to help cope with post-traumatic stress disorder.

Veterans and their families are expressing concern about the letters, which reveal who may be using cannabis to treat health problems, breaching their privacy.

"It has breached privacy on all different levels. If you follow the privacy protection act for health-care professionals, it breaks that," said Davis, who lives in Lawrencetown, N.S.

The letter was signed by Veterans Affairs Canada, but it arrived in a Medavie Blue Cross envelope. Davis said the envelope outed her husband as a medical marijuana user.

There are 3,000 veterans in Canada who use medical marijuana. The letter inside the envelope outlined the stricter limits from Ottawa on medical marijuana for veterans.

Security breach

Carla Murray, who lives in southeast Saskatchewan, said her husband, who is a veteran, also received the letter. She said he was furious.

"It's no different than them putting on the outside of the envelope that my husband is on OxyContin or that my husband is on a psychotic drug," Murray said.

"They took away the right of the veteran to choose who he does and does not tell what his medication is."

Murray said she is concerned about the wrong eyes seeing the envelope with their address on it at a time when there have been break-ins in her neighbourhood.

'They've made us a target'

"With the break-ins we've had around here, they're looking for drugs, pharmaceuticals and alcohol. If they know we have government-bought cannabis, how do I know we're secure?...They've made us a target," Murray said.

A similar incident happened in 2013, when Health Canada sent envelopes marked "Marijuana Medical Access Program" to medical marijuana users across the country. That case is still before the courts.

Davis said she blames Veterans Affairs Minister Kent Hehr for the newest incident.

"There was a breach. You have breached confidence and confidentiality and privacy here. What's to review? Is your review going to include hiring security guards to stay at our houses or give us alarm systems in our homes? Probably not," she said.

Situation being reviewed

Murray said the breach makes veterans who are vulnerable even more so.

"It's just a horrible thing to do to somebody whose mental illness has major security issues," Murray said.

Medavie Blue Cross told CBC News in an email Saturday that it is working with Veterans Affairs Canada to review the situation and address concerns.

On Monday, Veterans Affairs Canada sent CBC News an email statement that echoed the same message.

"Veterans Affairs Canada takes the privacy of veterans very seriously and the Department is reviewing this situation with Medavie-Blue Cross to ensure that the personal information of veterans is safeguarded at all times," the statement says.