I got this story in an email from my mom.
I have never heard of it before so I did a little research.
The original email:

Share with your sisters, daughters, nieces, mothers, and female friends. This
Incident has been confirmed. In Katy , TX.

A man came over and offered his services as a painter to a female putting gas in her car and left his card. She said no ,but accepted his card out of kindness and got in the car. The man then got into a car driven by another gentleman. As the lady left the service station, she saw the men following her out of the station at the same time. Almost immediately, she started to feel dizzy and could not catch her breath. She tried to open the window and realized that the odor was on her hand; the same hand which accepted the card from the gentleman at the gas station.

She then noticed the men were immediately behind her and she felt she needed to do something at that moment. She drove into the first driveway and began to honk her horn repeatedly to ask for help. The men drove away but the lady still felt pretty bad for several minutes after she could finally catch her breath. Apparently, there was a substance20on the card that could have seriously injured her.
This drug is called ‘BURUNDANGA’ and it is used by people who wish to incapacitate a victim in order to steal from or take advantage of them.

This drug is four times more dangerous than the date rape drug and is transferable on simple cards.
So take heed and make sure you don’t accept cards at any given time alone or from someone on the streets. This applies to those making house calls and slipping you a card when they offer their services ..

According to snopes.com the drug ‘BURUNDANGA’ has to be swallowed or inhaled and would not put off a strong oder. But if the drug was ingested it would cause dizziness at first and lead to passing out.

Most of what you can find about ‘BURUNDANGA’ on the internet says this story is a myth. However I feel it might be exaggerated slightly but there remains some truth.
The fact of the matter is that women can never be too careful.