Giant firms such as Wal-Mart (NYSE:WMT), Wells Fargo (NYSE:WFC), and Johnson & Johnson (NYSE:JNJ) seemingly defy logic in their ability to grow in the double digits year after year. Recent results at Johnson & Johnson illustrate why it is a heavyweight in the health-care industry.

JNJ is one of the most diversified health-care companies, with operations in pharmaceuticals, medical devices, and consumer products. Drug sales are the largest contributor to total sales and also very profitable, as operating margins run just less than 30%. Medical devices are a close second in terms of sales but have operating margins just more than 30%. Consumer is a distant third in terms of sales and profit margins, but is a very steady business.

First-quarter results offer a glimpse into how JNJ keeps growth chugging along. Total sales rose 15.7%, but most of this was due to the company's purchase of Pfizer's (NYSE:PFE) consumer health-care division and its Listerine, Nicorette, and Neosporin brands. JNJ also bought a couple of medical device firms, showing that it relies on acquisitions just as much as internal growth.

Operating earnings grew 14% for the quarter, continuing JNJ's trend of strong bottom-line growth. Earnings expansion may dip below 10% for the coming year, but the company has been able to grow the bottom line more than 15% annually for each of the past five years. During the same time frame, sales and cash flow have improved more than 11% on average.

For a better perspective on JNJ's growth profile over the years, investors can look back several decades, and even further. Fools might be tempted to worry about challenging drug-eluting stent trends that are also hitting Boston Scientific (NYSE:BSX), Procrit/Eprex drug sales as they go head-to-head with Amgen (NASDAQ:AMGN), or the overall health of the company's drug pipeline. I'm willing to wager the end result of these many moving parts will be steady and balanced improvements in sales, earnings, and cash flow for at least another decade.  

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Fool contributor Ryan Fuhrmann is long shares of JNJ, Pfizer, and Amgen but has no financial interest in any other company mentioned. Feel free to email him with feedback or to discuss any companies mentioned further. The Fool has an ironclad disclosure policy.