In celebration of The Motley Fool's 10-year anniversary, be prepared to savor some "Top 10" lists. Some will make you laugh, others will take you back; some'll peer ahead and others still will focus purely on investing. We started with 10 ways to make more money now (how better to enjoy the dog days of summer?).

Another way to make more money is to know, follow, and invest in some of the world's top drug companies. The drug industry has been the top-performing sector in the past 10 years and -- government willing -- could do likewise in the next 20. The question is, which companies are positioned for success come rain or shine?

Typically, the largest companies with the most money to spend on research and development, acquisitions, and strategic relationships (often with young biotechs) offer the surest long-term upside, coupled with lower risk. The giants also tend to have many of the most promising pipelines (drugs in development), because they have the resources to focus on unmet medical needs and to "try, try again" when a drug candidate falters.

So, who are the Big 10? According to, by measure of 2002 drug sales (just drugs -- not other products), the largest are:

  Company                 '02 Drug Sales   1. Pfizer  (NYSE:PFE)              $28,2882. GlaxoSmithKline  (NYSE:GSK)      27,0603. Merck  (NYSE:MRK)                20,1304. AstraZeneca  (NYSE:AZN)          17,8415. Johnson & Johnson  (NYSE:JNJ)    17,1516. Aventis  (NYSE:AVE)              16,6397. Bristol-Myers Squibb  (NYSE:BMY) 14,7058. Novartis  (NYSE:NVS)             13,5479. Pharmacia  (NYSE:PHA)            12,03710. Wyeth  (NYSE:WYE)               10,899
(in millions)

Of course, simply being large doesn't guarantee market-topping returns. Pfizer has traded flat during the last several years, as results have struggled to catch up to the steep valuation granted it since 1999. Bristol-Myers Squibb has been mired in accounting issues, while Merck, especially, has suffered from patent expirations.

But if you're considering your first (or another) investment in the drug sector, this is a great place to start. Read each company's SEC filings, learn what's in the drug pipeline, and look at valuations -- especially relative to free cash flow. This is investment homework that we've done regularly for our readers here at the Fool for the last 10 years, and the same we'll be doing in the next 10.

Fool on!