For today's call, I will report the financial results and Doug will provide a company update on the more recent developments. We will then open the call for your questions.
For the fourth quarter of 2011, total revenues were $38.4 million compared to $31.7 million in the fourth quarter of 2010, an increase of 21%. The infectious disease product category comprised a majority of the revenue increase, growing 28% versus last year along with 8% growth from our women's health category. Inventories at distribution remained at low levels, indicating that revenues in Q4 were reflective of that in user demand.
Global sales of infectious disease products totaled $27.3 million in the fourth quarter of 2011 compared to sales of $21.4 million in the fourth quarter of 2010. Strong sales from our influenza product line of which sales $9.7 million for the quarter drove the increase along with continued growth from our Strep A, RSV and herpes product lines. In the fourth quarter of 2011, Strep A and RSV each grew 8% over the fourth quarter of 2010.
Revenues for the women's health category increased by 8% in the quarter to $8.2 million due to the timing of orders in our autoimmune and bone health business and an 18% growth from Thyretain, our Graves' disease product. Our gastrointestinal product category revenues were $1.7 million, equal to the fourth quarter of 2010.Gross margins in the fourth of 2011 expanded nearly 400 basis points to 60% from 56% in the fourth quarter of 2010, largely due to improved product mix, manufacturing efficiencies gained at our Athens, Ohio, facility and continued cost reduction activities, the latter two of which we consider to be permanent. Included in cost of sales for the quarter were $2.2 million of intangible amortization related to the Alere lateral flow royalty buyout discussed last quarter.