A housewife in her late thirties, mother of two children, had an indefinite complaint about the indoor air quality of her house. Inspectors from a public health center treating the housewife's complaint quantified formaldehyde (FA) in high concentration exceeding Japanese national guideline of FA in some rooms of the house. We also determined FA and total volatile organic compounds (TVOCs) in higher concentrations more than the national guidelines. Remodeling of the house was performed to improve the air quality as follows. Vinyl wallpaper was exchanged to plant made paper, plywood made doors were exchanged to pure wood made doors, plywood stairs were covered with plant cork and so on. After remodeling the house, we measured the concentrations of FA and TVOCs again. The concentrations of the chemicals in the indoor air decreased which approve effectiveness of the remodeling. Moreover complaints of the housewife lessened. This also proved the effectiveness of the remodeling. Four years after the inspection, we visited the house again and found that the concentration of FA in the house was still lower than that of national guideline. The housewife was evaluated in a good healthy condition by her answers to our questions related to indoor air quality, daily life, physical condition, and so on.