The southwest area of a home is symbolic of a person’s abdomen, associated with the spleen, stomach, digestive system, female reproductive system, adipose tissue and muscles.  When there are bathrooms or kitchen in this area, those dwelling in the home are more likely to have health conditions associated with these organs, such as indigestion, skin rashes, dizziness, fatigue, difficult fertilization, or emotional fluctuations. 
The most basic and important way to address these issues is to keep the kitchen or toilet very clean.
For constipation, diffuse the digestive blend, ginger, and thyme.