Mercury in 6th house. 

So, lets see what Mercury can do in 6th house without any conjunction or aspect from any other planet. 1st lets see what these 2 things represent --

Mercury represents communication skills, marketing, calculative ability, younger siblings, hobbies, skills with hands, intelligence, quick decision making, logical thinking, youthfulness etc.

6th house is 1st of Dushthana Houses (houses # 6, 8 and 12) and 2nd of Upachaya Houses (houses # 3, 6, 10 & 11). 6th house represents things like diseases, debts, obstacles, enemies, disputes. litigations, under privileged people, pets, daily routine life, colleagues at work place etc.

So, in my experience, this is a planetary position which is meant for someone working in corporate world because 6th house is daily routine life or manual jobs and conflicts, Mercury is communications. So, this position shows that someone is using his/her communication in daily routine life to resolve conflicts, which is job of any Manager or CEO of any corporate. These people are really good with their communications, written or oral. 

This is also a good position to become a lawyer, as 6th house is house of disputes and litigation and Mercury is our communication/speech. So again, someone is using communication or speaking ability to resolve the disputes. 

6th house is also house of healing, that's why it also represents medical field along with legal field. Actually, Mercury alone may not make a person physician here but as Mercury represents Counselling and 6th house is about Healing, it shows a career in Health Counselling. 

6th house is also a house of under-privileged people and pets, so this position also shows that someone is involved in the service of mankind and animals. 

Good position if someone is dedicated towards service, either in corporate world or to mankind. 

Hope this helps. Thanks,

Swami Premanand Bharti