On Doctoring MEDLINE searches, with reference librarian comments

The question was

"Halitosis. A few patients have come in recently
complaining of foul-smelling mouth odor. After finding the bookshelf
literature to have very little to offer, we thought that perhaps the
computer literature would have something to offer."

1 :  halitosis.mp.         {368}
2 :  limit 1 to (human and english language)         {219}
3 :  exp Halitosis/ci,dh,di,pc,dt,th [Chemically Induced, Diet         {182}
Therapy, Diagnosis, Prevention & Control, Drug Therapy,
Therapy]
4 :  *Oral hygiene/mt [Methods]         {223}
5 :  *Sulfhydryl compounds/         {5738}
6 :  *Periodontal diseases/pc,dh,dt,me [Prevention & Control,         {1613}
Diet Therapy, Drug Therapy, Metabolism]
7 :  2 and 3         {112}
8 :  exp Halitosis/dh,pc,dt,th [Diet Therapy, Prevention &         {144}
Control, Drug Therapy, Therapy]
9 :  4 and 8         {0}
10 :  1 and 8         {144}
11 :  limit 10 to (human and english language and review articles         {4}
and (adult < 19 to 44 years > or middle age < 45 to 64
years > or "aged < 65 and over >" or "aged, 80 and over")
and english)
12 :  from 11 keep 1-4         {4}
13 :  exp Halitosis/pc [Prevention & Control]         {37}
14 :  from 13 keep 2,4,7-12,14,16,18,20-21,23,27,34         {16}
15 :  limit 14 to (english language and review articles)         {1}
16 :  from 15 keep 1

Reference Librarian comments

You obviously had some "MEDLINE fun" and that's exactly how to do it.
Play. Experiment. Learn. By set #8 you were on the right track.
Great job.

I had a minor brainstorm to offer...

You could do this...

exp *halitosis/et [Etiology]

... and thus you would learn about various causes of Halitosis. I
think that might provide some additional perspective.