Security researchers warn that spammers have already begun sending fake Google+ emails that direct users to rogue pharmacy sites.
According to security experts from Sophos who intercepted the spam campaign, the notifications purport to be welcome emails to Google's new social networking platform.
It seems the attackers took a real Google+ notification sent when a user shares a post with someone who is not yet on the network, and modified the links.
The shared message is deceptively called "Welcome to the Google+ project" to suggest that it is actually part of a welcome email.
However, it is followed by a link offering to "View or comment on [user's] post" and a button to "Learn more about Google+".
This button should normally lead recipients to the Google+ website and allow them to sign up for an account on the network which is still in a closed beta testing phase.
But all links in the rogue emails have been changed to lead to a rogue online pharmacy website, part of the Canadian Family Pharmacy affiliate program.
The site offers prescription drugs and male enhancement pills at reduced prices. There is even a 4th of July promotion, however, buying from such websites poses fraud and health risks.
"The spammers are no doubt hoping that the email will be too hard to resist for many people eager to see Google's new social network, although just how many users will be tempted to buy drugs online is a mystery
Graham Cluley, a senior technology consultant at antivirus vendor Sophos.
The fact that spammers are already showing interest in Google+, even though it hasn't even opened its doors to the entire world yet, is a sign that Google's new social platform will face the same kind of abuse that plagues Facebook and other similar sites.