Diabetes UK is launching a campaign to encourage lapsed members to return to the charity as regular donors.
It is the first time that the charity has approached members on the 50,000-strong database, many of whom joined when they were first diagnosed with diabetes.
"We're hoping that because donors are familiar with our work and remember the help that we gave them when they were diagnosed, many will respond positively,
said Pierre Scott, marketing manager of regular giving and donations.
"Although we're emphasising the confusion and pain many people feel when diagnosed with diabetes, it's not a negative message, because everyone who received this pack has gone through the same thing."
The charity believes that the initial mailing will boost its 16,000-strong membership base, and hopes to approach returning members with further campaigns including legacy appeals.
"We'll be happy if we cover costs over this mail-out, as we see the real benefit in bringing people back into the fold and establishing profitable long-term relationships,
Ad agency Ideas Unlimited has designed two separate packs to test ex-members' responses to different messages. The agency has created a pack asking donors to fund a specific research programme, designed to reiterate the importance of the charity's medical work towards finding a cure.
The second pack takes a general look at the different work that the charity does to help diabetics.
The campaign is due to launch this week, and the charity will roll out further targeted campaigns throughout the year.