The move is part of a bid to understand better the business it does with subsidiaries, suppliers and customers.
The joint IT and business-led project is contributing to the company's "Path to Growth" plan to cut costs by more than c1.6bn (£631m), increase operating margins and cut brand names from 1600 to 400 - within two years.
Following a successful pilot project this summer, Unilever has begun rolling out the data extraction system globally.
It will pull together information from market research firms and hundreds of Unilever's operating companies, partly to give senior executives an overview of how well particular brands are selling at large customer sites.
If Unilever discovers, for example, that a particular brand has lower sales than expected at certain large customer sites, efforts can be made to improve the product's performance.
It will be possible to use the extracted data to give pointers on which brands to cut and where to concentrate the advertising budget.
With 400 brands managed regionally and globally, rather than 1600, fewer systems will be required, says Unilever.
The company also hopes to gain an enterprise-wide view of how much business it does with particular suppliers. Objectives will be to negotiate better prices for bulk purchasing and cut the number of suppliers.
Unilever's size presents challenges in understanding its business relationships with customers and suppliers: it has more than 300 operating companies worldwide, with brands such as Dove, PG Tips, Flora, Marmite and Persil. To date each operating company has tended to operate autonomously.
The data extraction tool, from Acta Technology, collects batch and real-time data without any impact on the overall performance of the target system.
Unilever says it will pull together information from a wide range of legacy enterprise resource planning applications and numerous external sources.
The new system will extract data from software including that supplied by SAP, JD Edwards, Peoplesoft, MFG-Pro and BPCS and Oracle Financials.
The project is being co-ordinated by Chris Broe, programme director for the Unilever Information Programme, a joint IT and business team based at the company's head office in London.