diff --git a/scripts/_email_exclusions.py b/scripts/_email_exclusions.py
index 85ee257..ded5fa1 100644
--- a/scripts/_email_exclusions.py
+++ b/scripts/_email_exclusions.py
@@ -1,10 +1,17 @@
 """Shared recipient-domain exclusions for outbound cold-email campaigns.
 
 We self-host our MTA (transactional relays like SES forbid cold email), so we
-must protect our sending-IP reputation manually. The single biggest lever is
-NOT mailing the Yahoo/Verizon-Media family: those providers aggressively defer
-cold senders with "unexpected volume / user complaints" 421 responses, which
-poisons the IP for every other provider too.
+must protect our sending-IP reputation manually. The two biggest levers:
+
+  1. NOT mailing the Yahoo/Verizon-Media family: those providers aggressively
+     defer cold senders with "unexpected volume / user complaints" 421
+     responses, which poisons the IP for every other provider too.
+  2. NOT mailing Google CONSUMER mailboxes (gmail.com etc.) from a cold/warming
+     IP: Google hard-rejects them with 550-5.7.1 "this message is likely
+     unsolicited mail", and those rejections are reputation-damaging. (On
+     2026-06-08 a warmup audit found gmail.com alone was 77% of our 550-5.7.1
+     blocks -- 427 of 556.) Custom domains hosted on Google Workspace are a
+     smaller, MX-only signal handled separately in the per-vertical builders.
 
 Keep this list authoritative and import it everywhere we build audiences.
 """
@@ -29,9 +36,19 @@ YAHOO_FAMILY_DOMAINS: frozenset[str] = frozenset({
     "frontier.com", "frontiernet.net",
 })
 
+# Google consumer mailboxes. Google's cold-IP spam filter (550-5.7.1) is the
+# strictest of the big providers; consumer gmail accounts have the highest
+# complaint sensitivity. We hold these out of cold/warmup sends. (This is the
+# domain-string layer; custom domains silently on Google Workspace need an MX
+# lookup and are handled in the per-vertical builders, e.g. the healthcare
+# mx_provider flag.)
+GOOGLE_CONSUMER_DOMAINS: frozenset[str] = frozenset({
+    "gmail.com", "googlemail.com",
+})
+
 # The full set of consumer domains we refuse to cold-mail. Extend here as we
 # discover other reputation-sensitive providers.
-BLOCKED_EMAIL_DOMAINS: frozenset[str] = YAHOO_FAMILY_DOMAINS
+BLOCKED_EMAIL_DOMAINS: frozenset[str] = YAHOO_FAMILY_DOMAINS | GOOGLE_CONSUMER_DOMAINS
 
 
 def domain_of(email: str) -> str: